"Elite athletes" do a TON of UT1 and UT2 work, <=1hr 1x or 2x per day, with intervals and sprints mixed in a couple times per week. The idea is to incrementally notch your fitness up so your UT1 and UT2 zones are better and you can hold faster splits.
The reason we can't really train like the "elite" is because we lack the ambition and motivation to break our plateaus. There is no reason you cannot take a national team workout schedule and do it yourself. Will you be ripping 1:40/500m for 1 hour? Probably not in your first year, but you can row on their schedule and self-critique yourself with the readily available video taking equipment we have access to in order to work out form flaws.
I do agree though, that speaking individually, it's very hard to train at that level consistently.. we're all different, and we must do what is prudent for individual goals. I assistant coach and stroke our competitive boats at my club, so I have no choice but to train for higher goals
Going back to the point of this thread though - unlike sports where you're supporting your own weight, and would benefit from accessories like a weight vest, rowing is a seated sport and a weighted vest isn't going to do much for you. If you wish to use weights, I recommend power cleans and back squats.