Our BJJ gym has been starting from guard lately which I greatly prefer
This seems like a terrible way to train in my opinion. One of you starts already on guard and the other already with someone in it.
Honestly, I can't see the advantages it has over starting training on the knees. One method completely discards one of the steps, takedown or throwing. The other method in turn continues to discard the same step, and also discards starting from a neutral position and going directly to a position.
Conceding takedown position is terrible practice for every form of grappling including MMA
Training grappling without taking striking into account is also, yet it is done.
For MMA and self defense, they are specifically training for. I was not interested in BJJ myself because of sporting BJJ or Grappling competitions like the ADCC. I became interested because of the BJJ used in MMA, which is as close as we have access to what BJJ was really meant to be used for, and yet not ideal because of the rules, such as no elbows in the back of the head of the opponent.
Sports BJJ is a reflection of BJJ's popularity, which in turn is due to its use and success in MMA.
To me, someone pointing out the lack of training in Jiu-Jitsu in takedowns and throws seems wrong, even hypocritical, when in other more popular forms of grappling things like any form of submission and single legs is prohibited.
Interestingly, BJJ continues to be used successfully in both grappling and MMA despite this habit of starting on the knees.
We have a D1 All-American at my academy. Almost every time I've seen him rolling, he's on the bottom. If he didn't "concede takedown position", he'd never learn BJJ. And there would be no reason for him to practice pulling guard, because that's not where he wants the match to go. In competition he is absolutely mauling people from the top. He won the No-gi Worlds at purple belt, a couple of weeks after being promoted.
Not only that, jiujiteiros are mostly hobbyists. They are not people who want, and many cannot, practice takedowns and throws. What, by the way, would make BJJ just Judo or Wrestling with another name, so what good would it do?
Takedowns and throws hurts, leave marks, and it's not so much fun. People can just cross train if they want to learn other things.