If you've got bills to pay and kids to support, leaving a full time job to work on something with no income for several months is just not something most of them are going to be able to do. Even if they could potentially scrape by financially for a few months, there's no guarantee of any success, and the wives (3 different people I've known) have always said "no".

However, what I've noticed is that instead of "no, we can't do that now - let's try to work on a plan to set aside 8 months of savings to let you focus on your idea", it's been just "no, you're not doing that". But... are you going to divorce someone over that?