Look up the debate between big blockers and small blockers if you're interested in learning more; a quick summary, many people wanted larger block size so bitcoin could process more transactions.
I believe several newer core developers staged a coup to prevent this from happening, despite several of the longer-term contributors being in favour of it. The original contributors (sans satoshi, who was mostly inactive at this point), had their access to the git repositories revoked.
This video goes into a bit more detail (https://www.youtube.com/watch?v=XfcvX0P1b5g) but basically the people opposing a larger blocksize had financial incentives.. a lot were in bed with a company called Blockstream which benefits from their development on sidechains (now the lightning network). Had the block-size been increased, Bitcoin would be much more useful as a means of exchange (more transactions would be processed, and they would be cheaper).
This is where Bitcoin Cash is now, but it doesn't get the BTC ticker symbol because Bitfinex and other CEXes have a lot of influence as well.