As others have said, an SSD can make a Core 2 system very tolerable for every day use for most people. I put an old Crucial C300 64GB in a Dell Vostro with a Core 2 Duo (can't remember which model) and it runs Windows 10 just fine. My daughter uses it as a glorified CD\media player in her bedroom. Since it was free, it was cheaper and more flexible than a CD player, and unlike the cheap junky CD players out there today, I can just swap the drive if it ever stops reading correctly. It boots in seconds, responds quickly and runs smooth.
And then there are people that can get by doing actual WORK on surprisingly slow systems.
I put together a system for some relatives several (several I say!) years ago, and it's using a Pentium E5700 (Wolfdale-3M, 3Ghz, 800mhz FSB... similar to E8500, but less cache and slower FSB), 4GB of DDR2, Geforce GT520 and a 7200RPM hard drive of some sort. It upgraded to Windows 10 at some point and they had no problems using it until recently when it developed some irritating software problem causing a Windows service to constantly max out disk usage. They are STILL using it that way. I tried diagnosing it for a while, but the high disk usage makes it so slow it's excruciating. I am instead going to just put together a new system for them. They said the old one was totally fine for their uses (ebay listing, editing product photos, maybe solitaire, etc.) before the slow down issue started. I wouldn't actually do this, but I think simply upgrading that system to an SSD would probably be all they would need for 10 more years, barring any massive shift in CPU or memory requirements for browsers.
My wife was also using an HP HDX18 18" laptop she bought in ~2009, with a Core 2 Duo (P-something... a good one), a 9600M GT and 4GB DDR2 until summer of 2020 when it finally died. I swapped one of the 7200RPM hard drives for a 128GB Samsung 830 back in 2012, and put a more modern wifi card in it 3 years ago, but aside from that it was running all the original hardware, and she used it for all sorts of stuff with no complaints. I used it from time to time and it was always fast.
Time Machine = FIC PA-2013 2.1 - K6-2 500 - 256MB PC-100 - TNT2 Pro 16MB AGP - Labway Yamaha YMF719-E - Midiman MM401