The initial cost would be significantly lower because there'd be no previous owner to pay. Property values right now include the net present value of all expected future rents. The incentive to participate in the crowdfund is that the increased likelihood of the event happening is worth more to you than your share of money invested (like any other assurance contract).
Compared to buying a percentage of the company, it eliminates unearned rent; nobody is getting paid more than it costs to bring the factor into production.
Not all of them, no. Especially in 2020 many were forgiven. If it was a profitable endeavor (counting opportunity cost vs just investing elsewhere), then the private sector would have done it using collateral. And we're still paying for those bailouts today [gestures at prices].