I've done big model clear outs twice. Both times I regretted it in small brief moments, but never in earnest. By which I mean, two years or so later I might get a hankerin' to fondle that one expensive OOP kit I got rid of, but it's always a momentary thing. The next day (or even the next hour) I go back to not caring and being glad I don't have all those models I'll never build taking up space.
One of the reasons I dropped larger models in favor of gaming minis is because all this sort of hoarded old faff can fit in a lunchbox instead of taking up an entire closet. When I hear about gamers who have legit storage problems with their lead pile, my mind boggles a bit at the sheer number of individual models (and purchases) that implies.
The only purge I legit regretted was throwing out a few bins of accumulated kitbashing parts and materials. That became a sore spot later when I had to build some sci-fi stuff, and found myself with very, very little in the way of options. However in hindsight I still feel that was for the best, as the models IMO turned out better for it, in much the same way that genre movies sometimes benefit from restrictive budgets (it forces creative problem solving, which focuses and refines the final product). And going forward, I recently decided to start saving for a 3D printer, so while that's gonna take like a year or so to happen, it'll ultimately eliminate the need for kit/trash/toy bashing, so I'm feeling pretty secure about throwing all that stuff out.