Hub motors are not going anywhere. What is needed really boils down to geared hub motors that don't suffer from overheating issues at higher power. This way you get your single speed reduction gear to keep the motor lightweight while still being able to package it nicely into a bicycle form factor.
The Mac motor comes closest to that now.
in my opinion, is around 1000-2500W, which seems to be better suited to mid drives.
Not the way mid-drives are done on bicycles. Once you get into decent power levels routing that through the derailleur or IGH is insane. It's just really poor design. The way mid-drives are done on bicycles only makes sense in under powered bikes were you need to change gears to make up for the lack of torque. And the only reason anybody needs this is because of limitations imposed by government.
The ideal drivetrain for bicycles is the same as every other successful EV in existance: Single speed reduction. And it needs to be engineered to handle the torque of a BLDC motor. Which means on a mid-drive bicycle you can still pedal you need a left hand drive just for the motor. Just like they did on early motorcycles that were still transitioning away from "bicycles with motors".
But since nobody is actually doing that outside of motorcycles then hub motors are your best bet if you want reliable long-term transportation out of a 750w or greater ebike.
Bionx sucked because they locked you into proprietary controllers and batteries. For a 'DIY conversion kit' it was extremely hostile approach towards their customers. Bionx made nice motors, but there was no way in hell I would buy one because of this. I don't know much about GoSwiss, but from what I can see they were screwed from the get-go by being based out of EU as well as being hostile to their own customers in the same way that Bionx was.
I understand how important it is for these companies to maintain a dealer network and make sure that dealers make money from them in order to get the dealers to push their products onto the buying public... but you can't be hostile towards your customers and expect to stay in business long term. Especially when your audience is of the more technical DIY-type people.
Especially not when those customers can buy a 200 dollar kit off of Ebay or Amazon that does pretty much the same thing. Even if it's crappy quality and weighs too much it's still 1/10th the price.
Hub motor industry in the west world can only be hi tech development, for the mass production is Chinese and can’t be beat.
The idea that 'West is High Tech' may have been true 10 years ago, but nowadays everything is done in China. Not just manufacturing, but also design. If you want to do electronics development at scale you really need to go to China.
Doing it in USA is just like trying to run a marathon with one leg tied behind your back. In the EU it's even worse.