The factories are not "throwing money at it" at the moment. Gas Gas have Adam, montesa through Honda/repsol tony laia and Fuji, beta Doug and jeroni sherco cabby. I am guessing all the others have importer funding.
The trucks are all old, the gas gas one is ten years old the beta one i'm not sure about mont one is from the road racing team I think, sherco is again a few years old and not massive.
Minders and mechanics well I doubt its too much. In fact the only casualty on the wtc front has been Scorpa, which wasn't massive in any case.
So from going on what happened this year, it is sustainable at this level or more would have disappeared from events.
Much more important is the credibility of the championships which needs more entrants. Is no stop the answer? Is section severity the answer? Why have 4 or 5 french hopefuls quit? Why has Shaun morris gone? how long can Oliveras cary on? What happened to Gibert from spain?
Are these riders going to come back/would have carried on if it goes no stop?