it is so damn hard to watch lesser players now that we have been spoiled by the consistency of the top 4 for so long.
sousa hits every 2nd or 3rd ball into the net or out.
You are right on that. I think it's sheer fear that holds them back. Players are afraid of these players and they typically explode mentally way before the match.
Occasionally though we get to see some drama/upsets etc. but certainly not enough. The 90s had seen some seriously dangerous floaters. I don't really see it these days and in fact for a long time now. Federer's long winning streak is well contributed to that.