It is definitely possible to tell a story in a 30 minute time period, or even a 15 minute time period. Here are two recent ones:
This one is surprisingly quite good. If a group of fan-film producers made regular installments of this kind (Not a series, but a collection of unconnected, self-contained Star Trek stories) and those installments adhered to these new regulations, time restrictions, & content guidelines, I'd surely watch it, & commend them for being able to work within the format & still produce something worthwhile, especially if it was at least as well done as this example.
In fact, if there's any fictional universe which could best support that type of endeavor, it's the vast realm of Star Trek. There are literally hundreds of worlds, years of history, vessels/posts, species, & scenarios in which to frolic appropriately. Disheartening though it may be to fans of currently produced fan-films/series, to see it come to a rather ignominious demise such as this, (& gut-busting to those that made them, especially the ones who played fair) it would be absurd to suggest that anyone could rationally refute the allegation that Trek fan-film overreach has been monumentally irreverent for far longer than could ever have been reasonable.
Nope. A long deserved, official kibosh has finally & definitively been put people, & it's time to admit it, & move on with what CAN be achieved through what may not be an equally liberated playing field, but a nonetheless generous & fertile one, imho.