Here's a screenshot from a Feb 2012 video of the German men's eight training for the London Olympics. They appear to be doing a two-hour erg piece at 20 strokes/minute. The rower in the screenshot has averaged 1:51.4 for the first 62 1/2 minutes or so. That is 253 watts (~12.7 watts/stroke). There's no way to be sure, but I would guesstimate the targeted power output over that duration at around 50% of 2k watts. If so, 2k watts are 506 and 2k pace is ~5:53.6. That's actually probably a little slow for an Olympic-level male sweep rower -- I'd expect something more like 5:45 at that point in the games preparation cycle.... I'm confident that at 20 strokes/minute, everyone in that boat at that time was capable of holding my 1:44.5 pace (or better) for at least an hour, at something under 70% of HRR (heart rate reserve). At a rate of 17 strokes/minute they probably could hold the pace/power output for 45 minutes at UT2 heart rates.
Everyone is free to train however s/he wants to. Just because elite rowers do a lot of long-duration low-rate work at relatively high power/stroke values doesn't mean that non-elite rowers should slavishly copy them. If nothing else such workouts are boring as hell and chew up oodles of time. Moreover, IMO if you/we do essay those sorts of workouts, for maximum benefit it's important to balance them in a periodicized training plan that raises ratings/lowers durations as the targeted competition date grows closer. Low-rate stuff is fundamentally foundational; IMO race prep is a whole lot easier when there is a foundation in place. And I would suggest that more often than not, low-rate rowing is an effective way of building it.
Is it the only way to go? No. Hell, I've won maybe more than my share of age-group medals at competitions like Crash-Bs, British and European championships, the first FISA world indoor meet, and at times have held various age-group WRs. And I
detest long steady-state erg pieces, over the years preferring to do roughly equivalent volumes as equal work/rest intervals at similar ratings.* To my knowledge, though, I remain pretty much alone in this approach.... Your alternative, alternative method clearly works for you, and I cheerfully recognize the differences and the results.
* And since my diagnosis of type II diabetes back in 2017, I've been physiologically unable to do long, uninterrupted pieces on account of dehydration coupled with diminished blood glycogen. There's a serious danger of hypoglycemic seizures that could potentially kill me.