George can afford a few for the caravans he is sending. Of course they make chainsaw like powered Concrete/steel saws as well which are not all that expensive. Then there is also Jaws of life that can be stolen from fire trucks and don't forget explosives are not that hard to come by especially by cartels that want to distract the popo.
Walls slow them down but what happens after they get through them is what counts.
Slow then down is one of the goals. Stop if possible but no wall is ever 100% effective.
Slowing them down is good, delaying them as long as possible so sensors are tripped and an alert to Border Patrol Agents is sent and tells the Agents where the attempted breech is happening.
The border is long and remote, mostly, and an alarm tripped allows the Border Patrol Agents a location to head to so they can catch the illegals aliens at the wall or cuts down the time between the breech and arrival of the Agents.