Seriously, the players in the video I quoted have extremly poor footwork and form. They can't keep a rally going for more than a couple of balls, I just don't see how they aren't 3.0's. I know that it's 3.5 tennis, I would love to know the players names and look them up in tennislink because I would bet they are mediocre 3.5's at best.
Also people are asking opinions based on the videos alone, since that's all we have to go by and watching their form that's how I would rate them. I may be way off but just by watching the video that would be my thoughts.
I think the dynamics of a match are not the same across the board at each level. There are 4.0 matches that end in errors quickly. There are 3.0 matches that result in long rallies. It depends on how the opponents match up. Its possible they are weaker 3.5s or true 3.0s playing up, but I doubt it because they are playing #1 singles at 3.5. Another reason I doubt it is because I've seen solid 3.5s and above who look worse than this.
The reason I singled out your opinion is that you stated it in a way as if there is no way they could compete at 3.5. I thought I would chime in because I think that I would know more about 3.0 and 3.5 men then you do as I play against them all the time and you probably do not.