More and more games seem to suck on thier own, but can be great with mods. You have entire platforms like roblox where all the games are more or less mods. How long until the platform itself is community created and managed and the viability of games created by companies dissappears?
Counter Strike, Warcraft 3 DotA, ARMA 3 PlayerUnknown’s Battlegrounds, Momentum Mod, … All of these were mods that became so big they became their own games.
If you’re strictly talking about platforms though, you need support from the original developers,or the source must be easily editable (like the minecraft java edition). At that point it becomes pretty common for huge mods to be made which eventually end up managing themselves. The problem is that you need a lot of money to actually make new feeling games. And developers can’t easily ask for money for mods, so development time is quite limited.