I service many high rise offices, some which take up an entire floor or two, up around level 15.
My t/m was incapable of reaching these.
My porty was also a failure in that distances to fresh & waste water were a long way away.
Power outlets were at a minimum for air movers, plus the time and hassle getting them to those levels and moving them around.
NO air conditioning, UNLESS I wanted to spend $100.00 per hour for it, it would run the entire building, not just my areas.
Loading that price onto the job made it cost prohibitive.
Consequently, damp carpets, odor & condensation was the norm; which I was not prepared to put up with.
Encapsulation proved to be a winner in this case.
I actually got the original job a decade ago when one client was going to have their carpets replaced.
The carpet retailer told them to contact me, I'm still maintaining their carpets ten years on, plus other clients in the same building.
Shopping malls have also proved to be the same deal, security & safety will not allow the use of a t/m from the entrance/loading dock.
Again, no air con; after hours.
Sure, I could leave air movers and have to go back next day to pick them up, but time is money and these clients are budget conscious, so am I.
Again, Encapsulation keeps them & I happy, regularly.
There are places & times where a t/m or even a porty would excel, especially in the removal of heavy soil situations, but for maintenance, I prefer my Cimex & Sprayborg.