Not even so much that (which doesn't help any) but I was thinking more of the fact that the film (and any potential continuation of it) wouldn't fit with the grand MCU master plan. On the other hand, there's also Deadpool and it seems unlikely we won't get anymore of those, so maybe The New Mutants can exist in the same corner of the universe as that franchise.
The other big problem, of course, is the COVID-19 pandemic. We have no idea when things will return to "normal," let alone resuming regular film productions (despite tentative green lights in places like the Czech Republic), which have all have been delayed. Those delays cost money and there are a number productions much further ahead than any potential sequels to The New Mutants.