And jailbreaking was a creative source as well until jailbreaking (full, surviving reboots) went away. Yes there is still a sideloading community but nothing like what we were doing with Summer/Winterboard or the hundreds of random tweaks I applied to my phone back then. So many hours spent scrolling through new packages on Cydia.
I wish Apple would see that opening up their platforms actually leads to a better core OS as Apple borrows/steals from the community.