I mean, there's vacuum and there's vacuum. If you just need a lab vacuum line for drying stuff, I wouldn't say that's super expensive.

It only gets expensive when you get towards ultra high vacuum at which you have to lock out individual molecules including small stuff like hydrogen. This requires ultraprecise manufacturing techniques including the polishing and welding (and pump bearings e.g.) with lots that are not small in general, but still rather small in comparison with car sales.

If you need highly tighted autoclaves for high pressure, that will also get expensive rather soon.