Obviously there's start up costs in terms of both money and time investment but reloading for 300blk is about the best way to actually be able to shoot 300blk. When everytime you pull the trigger you're thinking "That was two bucks, that was two bucks, that was two bucks" it makes it hard to pull that trigger.
A single stage set up isn't all that expensive to get into and then you can shoot for well under 50 cents a round. It doesn't take that many rounds to cover the cost of the reloading set up. And once you've covered your costs... well pulling hte trigger and going "That was 40 cents, that was 40 cents, that was 40 cents"....
Will the ammo come down? Sure, there could be a breaking point where supply ramps up over demand and savings from making in bulk will in theory get passed down to the user. The question really becomes when will that happen. There is a little chicken egg thing gong on though. If people abandon the cartridge because there's no reasonably priced ammo then no ammo will be made in quantity and the price goes up. Vice versa if the round gets adopted more and more then more and more competition will come into play to get a piece of that demand and prices go down, which brings more people into the calibre.
It's the old betamax versus vhs kind of issue in a way.
But short answer the only way to shoot remotely affordable is reload.
Also try and determine why you want the cartridge in the first place, what you're looking to get out of it and have a realistic idea of what it can do. And what it cannot do.