As far as those TRS-80s, i would sell them vs throwing them away. The heavy ones were the Model III and Model IV's. I owned a Model I everything connected separately and a Model III all in 1 unit with display, computer, drive, and keyboard. The Model III was better in that it took up less space and had more memory, but being an all in 1 unit when it needed to be serviced it was a pita. I sold my TRS-80s years ago and I wish I kept them, although if I had them today they would pretty much just sit as antiques away from direct sunlight and almost never powered.
Planned Obsolescence is the driving force behind computers getting slower in some cases.
Usually its just that the complexity of the programs running increases and so the CPU/GPU eventually is burdened by computations that are beyond what the CPU/GPU's were originally designed to realistically handle. And so performance declines over time if your constantly updating to newest versions of software, installing more modern software, and hardware remains the same.
If you are someone who can get by with a system that is out of date but running software that is dated similarly to that of the older computer, you can use that system for many years beyond when most would consider it obsolete.
I for example have some computers that I run offline that are obsolete such as a Pentium III 1Ghz Laptop with 512MB RAM, and 16MB nVidia GPU that is horrible for web use beyond e-mail and simple google searches, but running it only offline with Windows XP SP2 with no further security patches or service packs it plays older games very well such as Diablo II and Unreal Tournament 99, as well as it still works perfect for serial connection to older serial port Cisco devices etc to make changes etc when most modern laptops do not have a DB9 serial port unless you use one of those USB to serial dongles etc.
Planned Obsolescence is basically designing products to only have a set life expectancy in which for computers and other computerized devices in order for the manufacturers to thrive they need to make sure that your a returning customer since they wouldnt make any money selling computers that last 15 years and so they engineer them to only last an average life expectancy, they also design them to have limitations to maximum resources and so motherboards are designed to only take up to 2GB RAM for example in which they could have been designed to take 4Gb or 8GB at the time, but weren't. As well as the CPU's for the motherboards are changed intentionally to make sure that a newer CPU type can not be installed into an older socket. ( *Although AMD has been really awesome with their AM2+ and AM3+ CPU sockets that allow for newer CPU's to be stuffed into older board -or- older CPU stuffed into newer board so that you dont have to swap out motherboards as frequently to upgrade systems. ) Intel though hasn't been as nice to make sockets that work among older and newer CPUs, although someone created a cool socket 775 mod to allow for Xeon server CPU's to be installed into some socket 775 desktop boards with a pin mask and redirection kit as well as cutting out some plastic bumps from the 775 socket.
As far as Planned Obsolescence and OS, its in the best interest of Microsoft to create patches where the source is hidden from view to be strategically inefficient if they have a newer OS out there that they are promoting. They want you to make the leap from your older OS to the newer one spending money to upgrade either in the new OS direct or a whole new computer that they get a piece of the pie on the sale of the computer since their newest OS is bundled with it, and so if they wanted to, they could make security updates that while take care of real security issues also are coded in such a way to create intentional lag to systems. * There is no proof to this since the source code to updates is hidden from view to inspect its intent, but I have a feeling that this could be happening.
In comparison Windows OS's seem to lag out faster than Linux OS's. And this may be because the source for Linux is out in the open, is coded more efficiently vs building onto old code that is riddled with inefficiencies, and there is no need to lag out an OS when its free to get the newest version of it. So there is no need to nudge people by lag to push them into a newer version of it. Also though to Windows defense its targeted far greater for malware and virus's that slow it down as well. But also comparing the 2 are like apples to oranges. They are very different even though similar.
The best running systems I have ever owned were ones that operated mostly offline though where without updates to software and OS, it runs as fast today as it did 15 years ago. But the Software and OS is that of the time period that it was originally created. But when bringing such a system that was connected to the internet back in the days of dial-up to modern internet connection while if you can connect it to the internet the internet speed is fast, the content that the system has to handle with flash and other content is beyond the capabilities of the hardware and so it either wont handle the content or if it does the performance would feel as if the computer is crippled.
For my online systems, I also perform rebuilds of them about once a year as for systems that are rebuilt fresh usually run far better than a system that has been running on the same build for 12 months with software added and removed etc. This pretty much cleans the registry out of garbage and gets rid of any inefficiencies in the location of data on the HDD in which the hard drive isnt fragmented, but yet the data's placement is not as cleanly located as it could have been such as after a rebuild in which software added is more likely to be placed continuous on the platters vs as scattered as a system that has had lots of data added and removed and some data not being movable such as large game files etc. Also it sheds junk from services etc that may be orphans from software installs that are no longer installed etc in which CPU performance increases because the CPU is less burdened running on a cleaner build. as well as free memory between the old build and new build usually also shows more free memory available after clean rebuild.
