@nlinecomputers Older generations have software patches for spectre & meltdown, so it's not like they're vulnerable unless running Windows 10 v1507 without any updates. I assume the initial release of Windows 11 would be pre-patched for spectre & meltdown.
Sure it's better to have hardware without the vulnerability, but natural attrition would take care of that over a few extra years.
Microsoft's end-of-support for 7-year-old hardware will virtually guarantee that there are less secure systems running Windows 10 without future patches after October 2025. The logic is not so clear as some are making out. There might be more vulnerable systems overall because of the decision to cut off 7th gen and older.