My anecdotal experience over the last 15 years of personal PCs.
I've had one case of Corsair memory which went faulty after a year (was replaced without question by the supplier) and around 3 PSU failures.
However, on the 3 times I've done upgrades (typically motherboard + RAM + CPU) in that time I've been able to keep my existing PSU without stability issues.
So I wouldn't say it's "insanity" to keep your current PSU when upgrading, but based on your experience if I had stability issues it may be the first thing I test.
Yea, I've ran bunch of office PC's with nearly 20 year old components 24/7 without any stability issues (acting space heaters doing CPU intensive tasks in winter).
No need to replace a quality PSU until you start having issues.
I've had one case of Corsair memory which went faulty after a year (was replaced without question by the supplier) and around 3 PSU failures.
However, on the 3 times I've done upgrades (typically motherboard + RAM + CPU) in that time I've been able to keep my existing PSU without stability issues.
So I wouldn't say it's "insanity" to keep your current PSU when upgrading, but based on your experience if I had stability issues it may be the first thing I test.