as a thought experiment, i believe no fallow no qt can work. probably what this means is that you may lose some or all your fish, but eventually you will be able to have a tank of fish. now even paul should admit in his early days of reefing back in the 70s he lost fish. so thats the model, add fish until you have a group that will live. never breakdown your tank, continue to add corals until they live, continue to add biodiversity until it lives. nobody will deny that they couldnt keep corals in the 70s. if you had it a week, it was a success.
logically this works. in fact in real application this works because my first tank was no qt or fallow. yes i lost fish - but everything was fine until i hit that tipping point or was it that i added the wrong fish. i could have licked my wounds and simply just pulled the sick fish and continued. really everybody else was fine. this was the point were i began to question if i was doing things correctly. not for myself of course, i was fine. maybe a bit emotionally damaged because i was somehow involved in the death of a pet. but really did i do everything in my power to make sure this fish had the best chance of surviving. the answer to this question must be no. no not because the fish died but no because i failed to take even the minimum precaution against disease.
well thats the rub, today its considered unethical to do this because we have a best practice of qt etc. the counter argument is that a lot of fish die in qt. this is also true because many people attempting qt are new at it and dont know what they are doing. so to fairly look at qt and fallow practices, we need to look at a professional like a marine biologist in the aquaria setting. the counter argument is that 99% of the hobbyist and incidentally the same group that are losing fish in qt arent marine biologist.
this also opens up the argument that people want easy and fast, yep thats also true. its part of human nature. i dont have all day to go on about this, but i do give credit to paul and others like him (he is not the only one -many people have older tanks in the same fashion) on his and their tanks. probably without people like paul, the hobby would not even exist today.
that said, we face a new host of problems today (some may not be so new, but maybe they are new in a new type of way). bad supply lines, misinformation, inexperience, mass supply and demand, greed...
to sum it up, yes no fallow no qt will work. you may lose some fish along the way, you may lose some corals along the way, you will not be able to keep sensitive species like powder blue tangs (immediately or maybe ever). and understand that you are starting in 1970 not 2021, so dont expect results like you might see on a developed mature tank.