Earlier quoted context omitted.
Instagram followed a similar trajectory for me. For a while, as a photography hobbyist, it was a far more "active" social community for photography enthusiasts than whatever came before (Flickr, Smugmug, photo.net, various niche forums). I made photography friends thru it that I met in person even when traveling overseas. This lasted maybe 2 years. Then all the "normies" got on it and my feed started to just be casua…
I never saw Instagram as appealing to photography hobbyists. Instead, I saw it as deliberately nerfing things where hobbyists have advantages (image quality, choice of aspect ratios, posting from desktop PCs), likely to increase participation by making it less intimidating to share snapshots taken on phone cameras. It's probably impossible to make something that's good for any kind of enthusiast that's also effective…
I agree with this 100%, on top of what you said remember that Instagram launched in 2010 as an iOS exclusive during a time where Apple was not particularly focused on camera quality, ignoring Android where there were numerous devices with substantially better cameras. IIRC someone was even selling one with an optical system in the ballpark of a low-end mirrorless. They also limited image resolution to 640 pixels square until 2015.