I'll say the quiet part out loud.
The reason so many users are set against Tesla switching to CCS is psychological.
It's has nothing with the connector itself.
They think that Tesla switching to CCS is opening the floodgate to non-Tesla users using the Supercharger.
The reason they keep insisting that non-Tesla users buy adapters to use the Supercharger is that it adds another barrier, which makes non-Tesla users less likely to use the Supercharger.
The reason why Tesla hasn't switched to CCS; the reason why the CHAdeMO adapter was almost always out-of-stock; the reason why Tesla hasn't bothered with the CCS adapter until now: it's all the same.
Tesla wants them locked in its walled garden. Tesla only want them to charge at the Supercharger and nowhere else.
They are so set against non-Tesla users that they willingly locked themselves in Tesla's walled garden.
For me it's how thick the CCS cables are, how stiff they can get in the winter, and how large the connector is. The Tesla system is pretty perfect in size. No little flap covering some pins or anything, I can do everything one handed. It's simple and elegant. At least for now, it also seems to be just as capable. There are rumors Tesla will bump V3 stations to over 300kW of power. If they actually can do that and the cables can handle it, even just at peak points, then those cables are pretty dang good right now. Three years down the road, maybe not, but maybe Tesla will be able to design something better while keeping compatibility with existing cars and their plug design.
I actually like the walled garden with Tesla, it keeps them honest and on their toes. If Tesla knows everyone can plug into any charger on the planet... well they'll say they'll keep working on the supercharger network to be number one but honestly what's stopping them from slowing down roll outs in states that aren't high in Tesla sales? As long as the car can go from point A to point B, well, it's covered. Right now Tesla sees a HUGE part of their fleet and where they travel/need to charge. If everyone skipped the Tesla superchargers because the EA charger was faster, newer, closer to food, etc, then Tesla could artificially think that route wasn't popular with the cars because their supercharger use was low(er). Yes I know Tesla can see their fleet, but I suspect they look more at supercharger usage than just where the cars are going. If a site is constantly 90% capacity than it might cause that location to float to the top to be built out more.
But why do I care if Tesla keeps building new sites as fast as possible? Because to me they are still the gold standard in charging. They still need those sites to work all the time. To be easy to plug into. To be fast. They need all these things to sell cars. It's a feedback loop and self check. If the chargers are getting worse the sales might slow. If the sales are taking off faster than ever, the supercharger team needs to get to work deploying more. Until there are big charging networks that are actually in the game to make money with a product that works all the time, I don't want my car to "rely" on it.
They're a great backup, and they are getting better. But to me, Tesla Superchargers still are the thing that makes long distance travel with an EV enjoyable. It might be possible with the other guy, but I think my stress level would be higher and my built in safety net buffer much higher if I knew 3rd party stations were my main option.
Five years down the road, things might have changed. But for now, give me adapters. 150kW is pretty dang good via a "cheap" adapter and 250kW or more off of Tesla superchargers is pretty good. I would like to see more power capacity at the sites before we start to routinely see 300-350kW charging. Even on a V3 station I've found that if it's full with a lot of cars at low SOC, you don't each get 250kW. It's MUCH better performance, but the site isn't delivering 2 megawatts of power. Everyone always wants faster, and I do too, but I'm ready for some refinement and improvement before pushing the envelope too much.
Double down on the V3 stations with the average travel distance like 50 miles vs 100 or 150 so towing can be done easier. Double down on the density so there is more of a backup in case a site goes offline or a whole town has a power outage. Build out more so it's easier to hit at lower SOC because there are just more options. Build out at national parks and more remote areas. Revisit the destination charger program and treat it like the supercharger program. Civic areas, large parks, zoos, malls, big metro movie theaters, sporting areas, build out 50+ destination chargers there and start to charge a small fee for them (maybe half the cost of supercharger).
Tesla can go so much further with their connector and ecosystem than they are right now. I think there are enough loopholes they can dip into the federal money by providing stations with extra plugs or a couple CCS stations at each site, and I think they can appease the Tesla owners with an adapter, but past that, I don't see a huge need to change other than change for it's self.