Probably the studios of they embraced television and more importantly don't sell off their film library for a quick buck but stay for the long they remain healthy and do not try swing for the fences in making big budget movies that failed.
Does this mean that there will be much less “epic films”? Here, by the way, an interesting point looms - quite possibly there will be less dependence of studios on road shows. In this way, it was just prestigious and luxurious pictures that were advertised - in particular peplums, high-budget military dramas, and musicals.
As for B movies, some will still be made but with slightly higher budgets and production values and we might see an earlier start to Made for Television movies that can be shown in theaters in the lucrative foreign markets.
It should be noted that many were created by independent manufacturers. After 1948, they had more opportunities for distribution of films.
Another way.for the studio system to survive in a modified way is that the studios take the stars in the shows that they are producing and own and put them in a B movie during the season hiatus in order to see if they have the potential to star in big budget films later on.
Except for James Garner there was no actor who stared on television who was also a box office draw.
But the examples of the opposite are known much better - Lucille Ball, Robert Young, Barbara Rush (hmmm .. maybe she will start her career as a television actress? Although I like her movies).
P.S. - in fact, television was not distributed until the mid-50s. Therefore, we can assume that here the competition at the very early stage isn't too noticeable.