If three reasonably healthy players are left in a no-fog game, then the game will continue perpetually.

1) The two weakest players will compete against the strongest player, forcing that player out of power, and 2) or 3) happens.

2) A different person becomes the strongest, and 1) is repeated.

3) The two friendly players both become exceedingly strong. So neither is bothered with the extra competition, neither will fight the third player, and instead they will fight each other. They drive each other down, allowing the previously isolated third player to become the strongest. 1) is repeated.

What do you think?

not necessarily perpetually, at one point, dependign on map size, 2 could come to such a degree that even though 1 is attained, the strongest player can overcome.

I think good tactics can allow you to overcome someone even with the No Fog and equal power balance.

Any games you can link that demonstrate your idea ?

Correct me if I am wrong. By creating a game with no private chat, it would be difficult to have a game the perpetually continues, with or without it being no-fog.

a 1v1 on duel map would last quite a while

but a large map, like E.asia, i could see taking a long time, with 3 players of roughly equal skill, low luck percentage, and no fog, and no cards.