Yes. Front pillars are thicker both for airbags, and also for crush/rollover protection, and rear visibility is bad because the beltline has increased, for crash protection and also for aerodynamics. Basically, cars now are MUCH safer than they were 10-20 years ago with these changes, but like anything, there's a price to pay, and it's visibility.

Luckily, rear cameras and radar sensors give me much better visibility now than I ever had with older cars that had more glass.

Yeah that's a bit shit nowadays; I've almost hit a cyclist at a roundabout the other day because he was behind one of the pillars, staying behind there thanks to the combination of his and my speeds. Always check twice.

That is totally true! I’ve noticed that even if did turn my head, I wasn’t seeing much compared to the last car I bought twenty years ago. The rear window is also much smaller than I’m comfortable with, but the sensors make up for it.

> (for crush/rollover strength?)

That's correct: a car's roof (or rather the pillars that hold it) has to be strong enough to not get crushed in case the car gets flipped. That's why pillars are so thick nowadays.