(moving the security bits up because I find it dangerous)
And the security argument is a strange one. If you never let the code "mature" then your defect count remains high. Which means there are likely exploits that can be quickly found with simple automated tools, vs being hardened enough that it actually takes real effort to find the ever more obscure cases. Which is why when you look at windows, a lot of the exploits recently are because they churned pieces of the OS that were decades old. And the "unsupported" versions of the OS weren't vulnerable. Similarly, the product I was working on a few years back dodged heartblead for the same reason. We were on a fairly old version of SSL only being patched with security updates. So, when the exploit finally became public we didn't have anything to worry about. Our version of SSL simply wasn't affected.
Its very dangerous to think that the most secure version of a product is the one that isn't battle tested because its being churned. That is just a reformation of the security through obscurity argument and assumes there aren't blackhats more than happy to hack a product and keep quiet about an exploit for years. Combined with the fact that now your hoping to randomly close these exploits through code churn just screams of a naive development model.
(comment on network effects)
I've rarely heard anyone mention any of the recent web based "innovation" as a reason to use photoshop over gimp, or even older versions of photoshop. OTOH, when I heard these discussions in the past, there were real hard reasons people didn't use gimp (color profiles?), libreoffice (document compatibility), etc. So the "innovation" needs to be something the end user finds useful, not just pretty buttons, or software subscription models.
Its obviously not enough to just appear to be a clone, there have to be real reasons to consider an alternative to overcome the network effects. When that happens you can bet people start choosing the "clone", which does in fact devalue the original offering. If a legitimate facebook , O365, etc competitor shows up you can bet people will start to switch even with the network effects of those two products. In the case of photoshop, from what i've heard a lot of people have been looking at Affinity's product. Which points to gimp still not being a proper alternative.
This isn't just software, its everything. Everyone keeps buying x86, until the day it turns out there is a cheaper/faster arm laptop. And it might not even be a change in the products themselves, the US automakers lost out in the 1970's because the market changed and they weren't as well positioned for it.