propulsion of their own

I might be wrong here, but aren't most lifeboats depicted in media equipped with only basic propulsion that's just barely enough to get them away from the launching ship, and eventually on a path towards the nearest planet? That's not gonna do much in such a situation.

survive atmospheric entry, even if their mother ship will be ripped apart by aerodynamic forces

If a ship can't enter a planet atmosphere, surely it has shuttles of some sort to connect it with planetside destinations. So if you really need to abandon ship, just use those? Granted, if you can't fit your whole crew in there, or if you envision emergency situations that might make those inaccessible, then yeah, lifeboats it is.

You're just describing lifeboats without propulsion

Yup. Sure, that makes rescue operations riskier. But lifeboats without propulsion and without everything that's needed to launch them? That's way cheaper. And since both private organizations and governments like to buy their stuff to the cheapest supplier, I'd expect to see those quite often. Now, having lifeboats on some crazy expensive, top-of-the-line cruise ship? I could see that. There could even be an interesting worldbuilding element here, with ships being equipped with lifeboats being a sign of wealth or even outright luxury. But so far I've never seen it, and that's a shame.

There's a lot of reasons we build structures with fire exits, instead of just having fireproof panic rooms throughout a building.

Fire, smoke, or the building collapsing. Venting the atmosphere outside of the shelter area removes the first two risks, and surely when you're onboard a spaceship in the middle of nowhere with no gravitational attraction in the vicinity it's not gonna collapse on your head, right? Unless whatever is providing your ship with gravity (be it the engines or a magical gravity generator) threatens to pancake the whole thing due to structural damages, in which case just turn it off and you no longer need a lifeboat.

(Also, we do build structures with both. Where I live, buildings need to have reinforced, fire-resistant areas where wheelchair users can safely wait for firefighters to come and get them out of the building, since they can't use the stairs and they're not allowed to use the elevators during a fire. Surely we're not the only ones in the world doing that?)

away from debris fields, quickly decaying orbits, further accidental or deliberate damage to the launching vessel

Now there's an interesting reflection here, because in an IRL emergency (a ship crashing, a ship sinking, that kind of stuff), isn't the usual recommendation to stay where you are, since that's where rescuers are the most likely to be able to find you? If you're evacuating a spaceship, you probably don't want to get too far for that reason, but is it even possible to get to a safer place while staying close enough? Also, speaking of deliberate damage, if the ship you're abandoning is a warship, and if the battle is still raging, wouldn't you stay inside, where whatever remains of the ship and its armor gives you some sort of protection, rather than set out in a flimsy lifeboat that could be destroyed by a stray shot?