But you can't plan for it if the company's owner hides it from you. If you think you need to lie to your staff about the company's finances, then you're an untrustworthy prick.
And if you get lucky, no one will ever know. And if you don't get lucky, everyone will know that you can't be trusted, and that could affect your ability to get contracts and employees at your next venture.
At least in my experience, while I haven't known the exact financial state of startups I've worked for, I've generally known the level of risk I was signing up for.
Your livelihood depends on so many people when you're doing a tech startup (your clients, the organizations running the internet, the government, the army, your neighbours) it's not even funny.
I left a reasonably stable small company to take a risk as employee #2. But where my experience may have diverged from what OP describes was in the hiring process. My new employer was very up front with the fact that, hey, it's a startup, and it might not take off. We discussed some alternative options & put some timelines in place to help reduce the risks I'd face.
Might everything fall apart tomorrow? Sure. But my company was 100% up front with me regarding my risks -- at least if we fail, we fail together.
I've had friends who have joined companies as the #1 where the owner completely misrepresented the situation of the company throughout the whole process, were burned, and are now working stable jobs that they hate. That's the biggest shame of all.
Your employment could end at any time. The company could be seized by the government as part of some investigation and shut down, the CEO could be hit by a bus, you could screw up in a big way and get fired. You could be hit by a brain aneurism and simply not be there to provide for your car payment and your wife's schooling.
Every employee is taking risk that their employment might end for any number of reasons.
This is one of the reasons that, when something like that happened to me, I said "That's it, my livelihood will never be in someone else's hands again" ... and have been self employed / doing my own startups since.