There is a team that handles any updates on the bitcoin core software and on the blockchain in reneral. But mainly there arr many trade-offs. They can make blocks bigger for example, for scalability purposes, but that might compromise security, make node setup much harder, increase the "oprhan" proportion between blocks and many others that we might not even think about. It is very hand to update the perfect system. You have to take too many variables into account.
It will take some time for the shitcoins to evolve and come up with better ideas and newer thechnologies that eventually can be implemented into btc if the community will agree.
The same thing is all over the tech world. Very hard to upgrade without screwing something else up. Patience my friend...