I think we've seen with the Sig P320 platform people love to modify their guns. As long as theres good aftermarket support people will buy, a lot of times to make it your own. Also I think most people don't shoot regularly and modifications are an easy way to personalize your firearm. For Glock specifically, i think they had their time 2010-2020 and now that we have all the new additions there's a new wave of competent firearms. The fact, that many come with optics cut, means less people doing slide mills or 3rd party slides. Trigger systems improving. These days you only really need ammo and range time.
These days, I try to run mostly stock configuration. The only changes are grips, and recoil spring. The manufacturers are finally getting better at stock triggers so a full replacement is not as necessary on modern firearms. I'm talking about Canik, Walther, Glock performance, M&P. You don't need to change things out to perform well like in the past.
I think there's a renaissance of 2A now and its one of the reasons I decided to start the site. I saw the changes with the roster additions and new blood coming in after 2020. We're at the beginning of what I think can be another strong period for 2A.
also forgot to mention, glocks are ugly. New guns are so much sexier.