By mean lifetime I mean “failure”. They won’t be any good

They don’t fail after 3 years, just a poor use of electricity once the next generation of silicon hits. It’s not economical to keep the old hardware running when it’s taking up rack space.

I assure you datacenter GPUs like B200 do fail regularly (within months in many cases), so much so that it's a problem for labs doing large training runs.

As long as they can be made to work in a consumer or homelab setting, they are still useful.

By “fail” I mean stop working