It might be too early to tell.

Those telehandlers and skidsteers are almost always rentals, so they get called off and picked up at the site. Moving heavy machinery is much more difficult than moving people, and all of your equipment is unique so it’s glued to that job site until it’s complete. Owning your own equipment presents its own set of challenges - you have to store it when it isn’t being utilized, keep excess capacity in case it becomes unavailable, fix/repair on your own, etc. All of the costs in the current installer model, while perhaps higher, are tightly coupled with the cash flows from the job portfolio. This might decouple the cash going out from the cash coming in, to say nothing of the fixed costs of having having hardware/software engineers on staff.

I really want this to succeed so please keep in mind this is just food for thought.

You're dead on with regards to the logistics involved in operating this equipment on site, we'll absolutely be facing each of the challenges you mentioned.

Time value of money. There is a lot of capital tied up in those machines. If they stop for a day there is no income from that capital.

Does not invalidate your point, but it blunts it

EDIT: Autonomous forklifts are old tech by now, most container ports are close to be fully automated as are tons of factories all over the world. Heck, we even have automated lawn mowers and hoovers...

And yes, as you said there is still the lost time value of money associated with any equipment that's not doing productive work.