I have read conflicting things so don't hold me to this, but on article I read said they delayed adding the laser links to the current batch of Starlink satellites because of concerns over how much would survive the de-orbit maneuver.
It's not just that they have plans to do so, they're low enough that they'll de-orbit fairly quickly on their own without active control (boost from their ion engines). Something pretty strange would have to happen for them not to eventually burn up.
Project Kuiper and Starlink both put the very large, thousands-of-satellites constellations low enough that trash gets cleared quickly enough that even a set of multiple catastrophic collisions is very unlikely to threaten most of the network, and even if they all just blow up, the pieces will fall down shortly and clear the orbit for reuse. For Starlink, drag is actually so high that they are using the solar array as a sail for attitude control.
I do agree that this is a real concern though, and we'd hope there's pretty careful consideration, considering the sheer number of satellites being launched. Still, space is big .. really big, even the space just above our planet.
I don't put it past humanity to not fuck up space. After all, look at all the plastics and waste in the oceans. Hopefully all these companies and FCC regulators are thinking far ahead, and require the right designs and safety measures to make sure we don't end up enclosed in a float garbage pile.