I like your idea (actually i practice it), but your investors aren't putting a lot of money in your hands so you keep it at the bank to them, right? They could do that for themselves.
By experience you don't need years on cash to survive in the long run, discipline and a business that makes sense is way more powerful.
But off course, months of runaway is necessary. More than that is luxury.
Investors put money in the craziest places, surely there's a public story stock right now that you think is inflated beyond belief and yet it trades at the price it does. It follows that investors will do crazier things than give you money to keep in the bank if you persuade them.
You tell them point blank, "we're hoping to make it big this year, but we aren't taking any risks and we're gonna keep enough cash in the bank for the 3 next years. If you don't like this plan, fine, you're missing a chance to buy a stock that's gonna shoot up 10x and here's why", and they buy your pitch, they're gonna beg you to take their money.
I'm not saying I can do this, I'm saying people exist who can, and there are markets where things are measured in years, and so you might want more runway because your progress is way slower than that of a YC-backed Internet monopoly wannabe.
By the way, MIPS Technologies was killed by genius investors who said "give us your $100+ million in cash or invest it" and a genius CEO who said "fine, you ain't gettin' nothin', I'm buying Chip Idea." It turned out that they didn't know how to run Chip Idea and ran it into the ground, and now they had neither money in the bank nor anything to show for it. This drove the company value down so much that Imagination bought it for $60 million (the patents were sold to a big CPU cartel for another $500 million, perhaps unfortunately as genius investors did not get quite the punishment they needed to learn anything.)
A CEO capable of persuading the board of directors to keep the money in the bank would have done better.
By experience you don't need years on cash to survive in the long run, discipline and a business that makes sense is way more powerful.
But off course, months of runaway is necessary. More than that is luxury.