The problem I think is largely due to lack of checks-and-balances. In the office you have investors who can apply pressure to management, who apply pressure to developers and hold them to a schedule; the lack of peer reviews (potentially) and transparency on the implementation are a problem too.

In the end, what is to stop the developers from walking away? They stand to lose nothing.

I think these platforms need to add legally binding contracts that will force developers to deliver or else they owe a large percentage of the money back (something like that).