MCU and X-Men are different. The films of MCU can fall into different categories. Ant-Man would fall into the Avengers film category and Ant-Man film category, but it won't fall in the Iron Man movie category, Cap movie category, Thor movie category. If Ant-Man fails, it won't have an effect on Thor/Iron Man/Captain America. It might have an effect in the Avengers 2, but not so much because they still have Thor, Captain America and Iron Man to carry the short-comings of the other MCU films.
With X-Men, they all fall into 1 category! Thats why its not a good idea for X-Men to release so many spin-off movies.
Making more X-Force movies and spin-off movies will have a direct effect on the main series because instead of just continuing the original series, FOX would have to use their time/money focusing on making X-Factor/spin-off movies. Therefore it would delay a potential X-Men 5 movie.