I agree but changes should have a background motivation or as the old saying suggests - why changing something that is working well (in our case is looking well)?

ch0k1

are there any good examples of successful sites that haven’t changed their UI over time?

craigslist is the best example i can think of, but even they have made subtle UI changes over the years.

Stacker News Homepage + Profile Design Ideas

No, I love changes - just don't touch the UI (look and feel) but instead as functionalities - all that will help users make sure the profile is legit and worth engaging like profile info, ranking data, trophies etc.