The point of contact between the bike and terrain: almost everything depends on the mtb tires. The more demanding cyclist equip themselves with different sets of tires according to the terrain they face in the races, characteristics and type of wheels mounted.
Overcoming an obstacle without stopping or having to put a foot down makes a insignificant difference: in addition to riding and technical skills, the rest depends on the tires, which thanks to their profile ensures the contact with the terrain and the traction needed.
In the MTB world the tubeless tires are very common: thanks to the liquid sealant in them also allows you to tackle the trails and more bumpy descents without the fear of puncturing; the absence of the tubes offers in addition the possibility of using them at lower pressures to further increase the grip on the rough terrain favouring the grip and reducing the risk of slipping. Coupled with sturdy puncture proof materials and reinforced walls on the sides makes them pretty much unstoppable on any surface.
But not all of us are professional athletes and that is why there are a wide range of foldable and rigid versions of the same tires available with the same tread pattern but with compounds progressively less refined to satisfy the wallet, without sacrificing quality.