Why don't some DSPs invest in larger DOT vehicles?

Is the wave of large gas vehicles (Step Vans and CDVs) going away from some DSPs? My second/current DSP does not have any and it's so whack because I'm seeing all of our Ford Vans and EDVs being FILLED to the the max. No space for walking at all. Instead we're investing in more rental gas vans this year? What ever happen to renting the Bright Drop? It's way better than the gas vans.

Is my DSP station overall just being cheap and not getting them or are we straying away from the step vans and CDVs now?