Why does increasing the surface area against a wall with wood (as opposed to putting this metal mount directly in the wall) provide more resistance against sheer force pullout (or a wall crumbling for that matter)?

I had a similar set up as this for about a year and it was attached to a cinderblock wall. The bag was 150 lbs and there were no structural issues from daily use.

I have a new house and want to put my bag back up but was looking for a better way to orient boards for additional support.

I don't fully understand the mechanisms at play. I suppose that as a force is applied downward at the produding end of the mount, the bottom part of the mount essentially stops the top from pulling out (sheer) by pressing harder against the wall and the wall in turns, and similar holds true if you pushed in up, down, lef, or right but the strength depends also on the grain of the wood, its thickness, and surface away combined?

So the weight of the hanging object would be causing more sheer at the mount points along the top board while the bottom board works to spread the force over more of the wall?

Would it be better to extend this "frame" downward to the floor so that the foundation receives the force also?

I feel like a brainlet and would like to set up a lab to test my theory lol. I am not confident at all even after using a similar set up for so long because it seems like magic and I am retarded. Please help.