It does become more difficult (most people don't hire people who are better than they are). That's different from saying that mediocrity scales better than skill. Skillful programmers understand points of leverage and reduce maintenance costs over time.
Purposefully hiring mediocrity? Big companies do it, but not on purpose. Survivorship bias is in play here. Taking that approach is a form of managerial cargo culting.
I definitely know some big companies that hire mediocre people on purpose to make sure they stay back and don't leave in a few months. Needless to say those places suck to work.
Purposefully hiring mediocrity? Big companies do it, but not on purpose. Survivorship bias is in play here. Taking that approach is a form of managerial cargo culting.