I saved Hitech's quote from the post you're referring to, because I thought it seemed hugely telling about the state of the game, with regard to first impressions, ease of use, learning curve, etc. Here it is:
I may be way off, but I think the Steam release was far more effective at getting users to try the game than any advertising campaign has been. In fact, I think it made it so easy to try the game that many people who were only marginally interested tried it - losing half of the 40,000 DLs suggests AH doesn't make a good first impression, or that half the people who DL'd weren't the kind of people who were going to stick around anyway - they might've been mildly curious and tried it out because Steam makes it so easy to do so.
Which is why I put stuff like finding a fight and long flight times to fights at #4. I'm not going to spend 3 hours to find the post, but I remember HT saying most never got wheels up. So it is doubtful that not finding a fight was a major factor. They never got that far. That's why I stated the last two the last two items in the list affected those who have subscription more than those you are trying to convince to start one.
It could be a training issue. I've been doubting that more and more. AH does a good job default mapping controls. Auto take-off is enabled by default. I've played many other flightsims. at least a good portion of those downloads would be players who have played WT, IL2, DCS, BMS, etc. I can not believe that most couldn't get airborne with a little effort if they has a motivation to do so. I think their decision had already been made before that point. They didn't see anything to change their mind.
Based off the reviews I saw on the Steam page and the data HT has posted, I still believe that 99.99999996% have already decided to uninstall at the point they get the trial\subscription message. They are just going a little further out of curiosity to see it, but aren't even bothering to get airborne.
Their expectation of how a subscription game should work has been shaped by market leaders like WT. They are expecting a portion of the planeset to always be FTP, not just a two week trial. Toss out what ever excuses you want, but the way the game is listed reinforces that. When they get the trial\subscription message, it feels like a slap in the face and a big middle-finger. It doesn't matter why the game had to be listed like that, it only matters what the outcome effect is.
Failing to adjust to the current markets expectations of how subscription games should be structured is the single largest point of friction to AH, IMHO.
Just as other sims that failed to realize how the market had turned away from pay-per-hour and died do to that failure. HTC saw the market shift then and was one of the very first to go flat rate. I fear HTC has failed to realize the market expectations have shifted again and a subscription model designed back when Bill Clinton was President might not still be effective in 2023.
I would never want to see AH go the micro transaction route like WT, but I think they do have a much smarter approach to keep contact with a potential customers longer with their FTP planes.
All should go read through the 300+ reviews on the Steam page. It can't be proven that every player who downloads has those reactions, but that is the data you have. Those are the only written (that I know of) explanations of why players who have downloaded AH were not sold. You won't agree with them, but that is self-selection. Since you are still here it is likely you don't share their view. Never the less, it would be unwise to ignore them. Those reviews should be read by anyone seriously wanting to understand where AH is failing to make the sale.
Or just believe what ever makes you feel good regardless of evidence. That is what most people do.