Do windhield mouldings keep the windshield from "falling out" ?
 

My 30 year old widshield mouldings are dry rotted and coming off on their own.
I went ahead and pulled them off, and plan to buy replacements.
In the mean time, I wanted to ask their purpose.
Looking online, it makes it sound as if you risk major damage to the car if you remove them.
I then see all of this advice comes from sources that want you to buy their window mouldings.
What has me wondering, is that i notice most modern vehicles have the windshield flush with the roofline, and there is no moulding.
The edges still have the moulding, but quite a few cars lack the piece that is at the edge of the roofline.

I like that clean look.

I pulled the ones on my door too. The ones that are supposed to fit snugly to the glass along the sill ( where you would rest your arm if you had the window open. )
I know these keep rain from entering the door, but I have to wonder - Since these are dry rotted, where has that water been going for the last few years that there has not been a good seal ?

The mouldings on my roof were also removed. ( heavy dry rot )
What is their purpose ?
I'm guessing just to hide the welds where the quarter panels meet the roofline.

What car? Anyway, the windshield mouldings are usually for aesthetics. The windshield is usually glued in place, with urethane sealant. I'm sure there are exceptions to the rule, but that's how it normally works.

Aesthetic.

Proper sealing of the windshield is essential though or you'll have water infiltration and wind noise.

1993 Honda Civic hunchback.

moldings
 

Around here, all late model vehicles have the bonded windshield, just as Blacktree spoke of. And the trim 'IS' just decorative.
I don't know anything about side glazing, other than that, 'flush' is aerodynamically 'GOOD', as LightShip L1 is doing on their new RV trailer.