The former Manchester United and England captain played his last game for the U.S. club earlier in October as they were knocked out of the MLS Cup play-offs by Toronto FC.
The 34-year-old, who won all major domestic honours during his career in Premier League football, has signed a deal to become a player-coach with Derby County in the Championship from January onwards.
Reflecting on his time in North America, Rooney spoke about his experiences with Ben Olsen's side over the past 16 months, including on the matter of earnings.
Days before Wayne Rooney's departure for the UK, he gave @TheAthleticSCCR his last interview in the US.— Pablo Maurer (@MLSist) October 28, 2019
We talked about #MLS officiating, coaching, expectations, disappointment, the media, the tabloids, his coaching ambitions, travel & much more. #DCUhttps://t.co/q0okMrgA05
The one-time Everton star was among the highest-paid players in the top flight of the English game during his peak years at Old Trafford, and was
still on a salary of $2.7 million (£2.1m) for 2018 following his arrival in July that year.
However, Rooney feels that pay is too low in relation to the turnover and profit generated by MLS, specifically in regards for up and coming homegrown talents.
“The salary for a lot of players [is an issue here],” he told The Athletic . “I think, for the revenue the league is bringing in, the salary is not high enough for in particular the young American players.
"I feel that they’re negotiating against other American players, they’re not negotiating against what foreign players make, I don’t think that’s right for them.
"They deserve more, they’re working the same as we’re working, they’re training as much as we’re training, and I just feel that sometimes they get took advantage of."
Rooney also added that he felt the nature of the MLS transfer market - where teams can trade players with little warning or tied down following a draft selection - is unfair to individuals.
“Players also get tied up,” he continued. “I think players should be allowed to move from club to club [more freely] - a bit more like it is in Europe, where if one club wants to sign a player, you have to pay money, pay more on the salary.
"I feel here players can get moved on too easily, they can have a family, come home from training one day and they get told they’re moving to the west coast, the east coast.
"For a family it’s really difficult to just up and leave like that without any real notice. Free agency is absolutely a big one for players over here.”
Rooney also paid tribute to the level of coaching from Olsen and his team at the Audi Field, but that he also feels that sides sometimes try to replicate European strategies to mixed results.
“From what I’ve seen, coaching - I can only speak for the coaches [at D.C. United], I don’t know exactly what the other coaches are doing - the coaches here have been good," he added.
"I do see the way other teams are set up and how teams want to play. I feel maybe - sometimes you see it with the U.S. national team - sometimes players can get over-coached.
"I feel that maybe be where the coaches over here are trying to do too much with the players. It’s a simple game but they see a coach like [Pep] Guardiola and they say ‘oh we have to try and do what he does,’ and they shouldn’t, necessarily."