They own IP but there are lots of valuable things you can do for a startup that don't involve important IP. For b2b you can start talking to potential clients

They own IP but there are lots of valuable things you can do for a startup that don't involve important IP. For b2b you can start talking to potential clients in the space. They don't own your network. For b2c you can start finding communities and building an email list. They don't own your audience. This is great because as a dev it forces you to do the hard stuff first that has the biggest impact on your success or failure. Not coding which is the fun easy part(for coders).