Nope, I don't think this is an issue and actually quite silly to think they are overworked. In the mid to late 90s and into the early 2000s, there were so many pro-am events, particularly for top US skaters. Butyrskaya even skated in 10 or 11 international events the year she won Worlds. Almost ALL top skaters starting in 1996 were doing three Grand Prix events as seeded skaters (one non-scoring event) in 6 weeks. Europeans, the GPF, and Worlds were all much closer together than they are now. On top of this, remember that Euros, Worlds, and World Juniors had a qualifying round for a long while and the GPF even had three rounds from 2000-2003, two of them often occurring on the same day.
The World Standings only allow for Worlds and 4CC/Euros in the first column - maximum 2 events there per season and most skaters obviously want to be in both events. Grand Prix, the second column, is a maximum of 3 events per year if skaters make the Final. Obviously they want to be there as well. Up to 5 events now. Skaters can compete in up to 3 Challenger events, with 2 (potentially but not necessarily) counting in the world rankings. Possibly 8 events (top skaters in the GPF plus a full 3 Challengers which is highly unusual), plus Nationals. And it's pretty spread out between September and March. The skaters we see in a lot of Senior B's are ones maybe not the most likely to make the late-season Championships, and probably want to compete as much as they can anyways. I don't think anyone is overworked.