With these kinds of possible sales numbers I don't understand why the big publishers don't adopt the age old music/film industry practice of having 'sublabels' that put out stuff that is more experimental and lower budget. Hell they could even craft an experimental mechanic into a small game, sell it digital only (Steam, etc.) and if it's successful roll it up into whatever multi zillion dollar 5-years-in-development title they currently have going at a "AAA" developer. Lessen the risk of a huge title bombing (since some of it has already been released via smaller games) and maybe even keep staff on instead of hiring and firing during every development cycle.
Yeah sure not everything is going to be successful, but if the budget is $200,000 and 3 months there's a lot less at stake than when it's $20 million and 4 years or whatever.