Not exactly. Apple stops shipping OSX updates for older Mac Pros, so eventually, you lose software support. I have a Mac Pro that no longer works with Mountain Lion. Is it missing some kind of hardware needed to run Mountain Lion? No. Is there any reason it shouldn't be able to run it? No.
As a result, I could not get upgrades for some software that required Mountain Lion to use. That, combined with the lack of upgrades, forced me to replace my Mac Pro with a custom built Linux box. It now sits idle in the corner.
Okay, so it's not black and white. Sure, my android phone from 3 years ago can't run most newer apps. But it can still run the things I had on the phone at the time. I guess what I was getting at was that Apple (or Google) doesn't come and take the device away from you once the product line has been EOL'd.
As a result, I could not get upgrades for some software that required Mountain Lion to use. That, combined with the lack of upgrades, forced me to replace my Mac Pro with a custom built Linux box. It now sits idle in the corner.