old Macs don't go obsolete, they just are no longer 'supported' when newer upgrades to software and OS's come out... so what programs you are using now will still work, just won't be newer updates. and new programs that come out may or may nor run under older os's...
so rest assured, so if it works for you now, it will still be working in 10 or 15 or many more years after now. (old capacitors aside.)
I don't know where these malicious rummer come from, but suspect old windows users still have grudges...
Regards, Sandy
P.s. my old 2012 27" iMac under High Sierra was working just great till we had a major flood in my city, and while I moved it to higher ground, unfortunately all they wire and circuit breakers etc got wet and when I plugged it back it fused... if not for that I would be typing this on that beloved old computer.