You can proselytize all you want for thousands of years and you will never convert the whole world at once.
It also doesn't matter if his tricks stop being effective if he can still sell them effectively. He doesn't care about integrity, clearly, so that wouldn't be a problem for him.
Not true or else leetcode would be gone. They made a lot of money off the old paradigm and somebody will certainly take advantage of whatever comes next
The same goes for hiring tricks. When some hiring signal becomes a trick that gets passed around by influencers, it ceases to become a useful hiring signal because everyone is gaming it.
If this guy started advertising his process, everyone would start doing his process and it would stop working.