+1 bulbs are what you need
+2
In the mid 80s my (first) job was working in a automotive lighting design team.
At that time Europe had mainly adopted bulbs in their headlamps and U.S. was still using sealed beams. The issue with replaceable bulbs is that they can move and when the filament is off the focus point of the reflector the headlamp can lose power and/or produce hot spots which can dazzle an oncoming driver. Also the initial quality of bulbs was not always as high as could have been hoped for - if we got a 'perfect' bulb we kept it on one side to use in the lamps sent for homologation testing!
The sealed beam keeps the fixed filament in one place.
U.S. at the time insisted on the consistent quality of fixed filaments.
The downside of sealed beams was the cost of replacement and the failure of sealed beam output to keep up with bulbs.
Another factor - maybe the most important in America changing - was that sealed beams tended to be limited in shapes and bulbed lamps gave more scope in lamp dimensions. For example - in the UK depth of lamp became very important on vehicles such as the Metro and the bulbed lamps allowed advances in reflector design to cope with this.
American opened up the market in the mid eighties to allow replaceable bulbs - I assume this is still the case.
In the past thirty years bulb design has continued to advance and improvements in build quality has helped the stability of filament location. So I doubt there would be any need to move back to sealed beams.