Star Trek

Because then they would not have been able to conquer and exploit the Gamma Quadrant. At least, not for a few more centuries.

Somehow I doubt Sisko and DS9 would just stand by and let Tain do that. And if they engaged DS9, that would put the Cardassians and Romulans in the uncomfortable position of being at war with the Federation possibly. Rather counterproductive.

Couple it with the fact that Central Command could more readily stop him too. Not to mention Tain said he was coming out of retirement. Much easier to come back to Cardassia as the man who destroyed the Dominion than the man who just closed the door and ran.

Well to collapse the wormhole the Federation had to set up some special technobabble beam. By Inferno's Light I believe it was in. But a founder sabotaged it and configured it to reinforce it. So chances are Tain didn't have the know how to do something like that.

Really his whole plan was flawed. Even if he had obliterated the Founders homeworld, there were bound to be any number offworld, and his assumption that killing the Founders would cause the Jem'Hadar to run out of white. Doubtful being the Vorta handle that little detail and they don't kill themselves out of shame if a Founder dies.

So yeah, the Jem'Hadar in all likelihood would come screaming out of the wormhole in a fury of vengeance with no minefield or Prophets to stop em. Good job Enabaran, you almost doomed the whole Alpha Quadrant.

I think it's because Tain thought the Founders would figure out a why to reopen the Wormhole eventually. And the Cardassians were ruthless. They probably figured why just cut off the Dominion's route for an invasion when you can totally annihilate them instead. And I also agree with the thought he wanted bragging rights that he destroyed an enemy of the Cardassians. That's my opinion anyway.

That is the best way to sum him up.

The wormhole was under the control of the Federation and the Bajorans. Destroying it would have severely strained relations with them.

Although when Sisko tried to seal the wormhole by collapsing the entrance, provided by Dr. Lenara Kan without harming the Prophets in In Puragatory's Shadow. They failed. Enabran Tain wasn't also succesfull when his Cardassian & Romunlan fleet attempted to eliminate the Founders.

Even as the female Changeling stated in Broken Link to Elim Garak "...All Cardassians are dead...They were doomed when they tried to attack us...", since the Dominion armada came through the wormhole those joined forces with the Cardassians.

Tain could just close the tempel of the Prophets alike the UFP would have, but none of both did it finaly.

This would be my rationale.

That's because they got sabotaged by a Changeling. The plan probably would've worked if that didn't happen.