Stu, when your training is all on the job, the job is the training. Overworked is the adjective that working stiffs apply to themselves. Many of those who treat indoor rowing as a fulltime job are post-retirement age or younger folks who are not employed. Work does fill up the days. Are they overworked? Are they “pacing themselves” to complete their contract with the monthly or yearly metre challenge? Or both?100km every day, no injuries, no illness, no bad days, no over training?? I have seen someone ran an FM every day for a year, and that was considered close to the boundaries of what is possible.
My best guess is that, in addition to “time on their hands,” chronic physical illness (search Diane Brennan/fiber myalgia) and possibly mental stress attributable to loss of friends, loved ones, and better days are significant impetus to taking up a physical activity which distracts from pain, self reflection and self pity.
Scepticism with regard to the long term sustainability (or even possibility) of daily low intensity erging equivalent to 2 FMs+ is justified imo. But condemnation of all who claim to do this as cheats and liers would have to include some who, however improbably from our pov, very likely have done.
Agnostic suspension of disbelief is advisable for those of us who have yet to take all the twists and turns in this sporting life.