Let's take prod DB access: Im not saying make it super locked down, Im saying set your DB security group to only be connected to from your API security group, and set an email warning when an instance launches in that group. Doesn't stop your engineers doing it, but it makes it pretty easy to shout across the office "Hey, who is fucking with prod and why?" Takes like 30 seconds to configure on AWS.
There are serious questions about why your CEO can launch that instance though, and that sounds like massive policy failure. Again, restricting the CEO IAM from launching prod instances takes 30 seconds. (And all your non-engineer accounts should be IAM restricted!)
Ignoring that your probabilities don't work out, Id argue that the situation is really remove 5 bullets or add 1 chamber, and people pick the chamber purely because it's constructive, not out of genuine cost-benefit analysis.
"If I had 3 hours to chop a tree, Id sharpen my axe" -- I think startups are too hasty to chop, because that's being productive, right?
To be honest, not in any of the several places I've worked. And I'm a security engineer. Lean startups are desperately trying to prove their product; time is spent on reliability, performance, and security almost entirely reactively and not proactively.
I'm not saying this is a good thing. Bad security (and reliability) posture early on inflicts multiples of the original mitigation cost for years. And yet, it's rational. Time spent securing systems from your own employees when you're tiny is time you're not building your product and finding your market. It's a perverse game of Russian roulette: there are 99 bullets and one empty chamber. The analogy is going to break down here, but spending time and money removing one bullet (1:98 chance of death) is less effective than adding another empty chamber (2:99 chance of death).
Especially when having direct access to the database is insanely useful to fix the problems that moving fast and breaking things inevitably causes, only a tiny fraction of startups are going to enact the kinds of measures you mention.