Go-busters the Movie had a run time of thirty minutes so this trend is still recent.
Now unlike the Buster's movie the other movies don't really have a difference in the quality. Going back to the Shinkenger movie nothing looks that different. Whenever a series gets a movie there is usually a big change in how things look. Remember in PR Samurai they used both of the movies for the Clash of the Red Ranger special and the Go-onger vs Shinkenger footage looked different, but the Shinkenger movie footage looks just like the series. The older movies have done this as well as it just kills the feeling of a movie as it still feels like a rejected episode for the series.
Boukenger used this mech for the movie and two episodes.
The biggest gripe I have with the Sentai movies is then how unimportant they are to the overall canon of the series. As I said the movies feel like rejected episodes and don't add any character development at all. I mean the characters do learn something, but do we see this in the series, not really. Heck even the main villains aren't even involved in the movies. The overall movie just feels ignored then and just bringing it back up in one episode doesn't count. Kamen Rider Double movies had some big connections to the series and other movies. The NEVER group and how they are zombies actually come up in the series and then the group as a prologue movie. Kamen Rider Skull is a really big character in the overall plot when you learn about him, he was even connected to Shroud. Heck most of the time when the movie mech or weapon comes into the series they just use it in a Sentai movie at times.