If I ran Googles program, I would immediately 10x all payments, unironically. Yes, that means paying 1 million bucks for something you previously paid 100k for. Drop in the bucket. You also get a ton more eyeballs on you, letting you patch everything ASAP.
But they dont do this. I dont know why. Security through obscurity? I suppose that works if you are myspace.com in 2021. Nobody likely gives a shit to try and hack it, but at the end of the day this is still google so that really doesn't apply.
The downside of not paying handsomely is people realize they can make more money selling to third party vendors, (which some do) then every once in a while you get a bad PR story showing that your stuff was hacked and exploited for months/years and it potentially knocks a few points off your stock price.
Money is really the end all be all. If you pay more than third party vendors, I can see almost no reason people would sell to them. At that point, your only adversary's are gov employees of nation states and the staff of companies dedicated to finding vulnerabilities.