Dave, Dave, Dave,
Sure, Pull out a classic like a "57" Chevy for your example.....

make it hard to rebut that
The reasons are many...
Some have done a roof raise and need the caps for the new roof line.
Many have re-skinned and want the smooth sides.
Others have actually saved the bus by capping instead of scrapping due to rust in the front.
And many just like the look, you know, there bus, they want it there way.
Hmmm, did that 4104 come with a turbo, or did you UPDATE the power plant.....

Don't tell me.....
Cliff