The problem with bodyweight training is that there's no smooth gradient from wall sits to, say, pistol squats. The difficulty increases lumpily and frequently requires a new motor pattern to be learnt.
Whereas going from a 20kg squat to a 100kg squat can be done 1kg at a time with the same movement pattern throughout.
For people who genuinely can't or won't go to a gym, I'd first suggest installing a power cage, adjustable bench, barbell and some plates. Failing that kettlebells and resistance bands. Only after those are exhausted would I suggest a purely bodyweight training regimen.
Whereas going from a 20kg squat to a 100kg squat can be done 1kg at a time with the same movement pattern throughout.
For people who genuinely can't or won't go to a gym, I'd first suggest installing a power cage, adjustable bench, barbell and some plates. Failing that kettlebells and resistance bands. Only after those are exhausted would I suggest a purely bodyweight training regimen.