Syfy cancelled Stargate SG-1 because the network was pivoting to putting more effort into their other shows like Eureka which had a more general appeal. The writers snuck this cryptically meta exchange into S10E18 “Family Ties” poking at the network for how they felt the series was being mistreated.
In my opinion, it was a mistake to make seasons 9 and 10 of Stargate SG-1 instead of their original plan of making it a spinoff called Stargate Command. If they would have started fresh as (technically) a new series, I think it would have been overall better for the long term health of the franchise.
10 seasons is enough.
I like when a show has the grace to end when it’s still good. Too many (mainly US) shows just keep going and going until no-one cares when they are cancelled.
I think 11 or 12 would have been perfect to wrap up all the story bits. I loved every bit of the show.
The problem was the network dropped them the ONE FUCKING TIME they thought they were getting another season, so they assumed they had more time to flesh out the end.