So: a 6-minute control saves time, while a four-minute control wastes more time.

Besides, Eric wrote that a strong player will win against a weak player in 4 minutes. And that's the problem! If you play worse, firstly, you have even fewer chances, and secondly, you have even fewer chances to learn at least something.

That's not what I was talking about. Conditionally, our players can be divided into 3 groups. Group 1 is experienced players who have played online a lot, and almost all of them understand the advantages of 6-minute control.
Group 2 consists of players who have recently started playing online, but already understand the game, analyze replays, and try to buy the 8th hero as soon as possible; they see cans and naga banks on the map, etc. These players are open to dialogue, and you can explain the advantages of 6 minutes to them.
Group 3 is what keeps the forum alive – the influx of new players. Most of them hang out in topics like "...which level 5 unit is the strongest...", but some of them also reach the online forum. And the first thing they do is read the rules. This person has not had the opportunity to play the game to the fullest before; in battles with the computer or a friend, 1-2 minutes was enough.
And now, this unprepared person is hit hard by the 6-minute control. You can give arguments to a prepared player that 6 minutes is even faster than 4, but for a beginner, it's too much. He's not that much of a fan of the game yet. He plays the map with the computer or a friend for 3 or 4 game months, multiplies it by 6-minute control, thinks badly about online play, and leaves. A completely new person in online play is not yet ready to analyze replays from games with experienced players; it takes time to get to that point, and he will hardly save the game at first.
He will either give up on learning online or go to other forums where the time control is smaller, or even to other games where there is also online play.

In general, groups 1 and 2 will find common ground with each other with 6 minutes, but group 3 will not.
We are definitely losing ground in attracting new players. But otherwise, I am not against 6 minutes at all.