Setting up your own Prop firm?

Has anyone ever done this?
Seems to me that you just pool together your funds and start trading - am I missing something? Is there a minimum number of traders/ level of experience required? I presume that as it is your own funds (not investors) you wouldn’t need any licences as such? If you can set up a prop firm as an individual what are the advantages/disadvantages of setting up a prop firm vs retail trader, I’m guessing tax?
Apologies if this is a stupid question, it just seems v simple, no? Bring me back to reality pls! I haven’t mentioned but I take into account overheads such as desk space newsfeeds sqwack box etc. Thanks