Let’s compare my process to what you’re used to by shedding some light on problems with using a truck as a power plant, bringing hoses in, and leaving a door or window open somewhere:

Pollution Concerns – The EPA wants to ban it entirely. I use less than 15 amps of clean electric power. The fact that I can accomplish a consistent extraction rate of over 94% is a HUGE feat of engineering!
Suction Variation – Suction varies greatly from many factors, especially elevation down from the truck (e.g., basements). The moving air loses power to pick water UP that far, leaving dirt behind. My source of suction stays a constant distance of less than 12 inches from the work surface.
Filter Clogging – Suction is lost as filters clog. On truck-mounts, checking filters wastes 5–10 minutes. On my system, I see debris in real-time, clean it immediately, and see stains and dirt coming out – which helps me know when your carpet is actually clean and prevents over-wetting.
Aging Equipment – Truck-mount blowers beat themselves to death over time. Many operators use worn-out equipment. I can restore my suction to new factory specs by replacing one $130 part. It’s more economical and consistent.

So if you see a truck-mounted operator advertising an extraction rate comparable to mine, they can’t deliver that consistently. Real-life conditions in YOUR home are too unpredictable.