Dresden is truly blessed with cinemas and has four European Network cinemas. Three of those have assigned seating, though none do price discrimination based on where you sit. Culturally the assigned seating isn’t taken very seriously in those four cinemas, though, to the point where staff in one cinema sometimes tells visitors that they can sit somewhere else if they want to. In practice we still try to get seats where we want to sit and stick to them (front/middle, away from other people), though if people come in and sit right behind us we might change rows.
With new ticketing systems and online booking being introduced I think there has been a shift towards assigned seating. I remember the first time I was in a Dresden European Network cinema (Schauburg in 2015, that’s the oldest cinema in Dresden, 1927) and there either being no assigned seating or a seat printed on the ticket that no one cared about. We also weren’t asked where we wanted to sit. That has changed with a new ticketing system and now we are always asked about where we want to sit.
I think these ticketing systems come with assigned seating and that’s also a factor in assigned seating being introduced.
Notably, the one cinema that doesn’t have assigned seating also doesn’t offer online booking or reservations at all.
The four big multiplex cinemas in the city have assigned seating and do price discrimination based on where you sit – so it’s taken somewhat more seriously there.
So, yeah, my guess would be that the role online ticketing and the respective software/service/devices those cinemas use for that do all play a role in what role assigned seating plays and those can also trigger a cultural shift from sit where you want to assigned seating. (I have vivid childhood memories of my hometown long before online booking with price discrimination sections but no assigned seating in cinemas.)