It's always a gamble to be an early adopter of calibers. Very few are able to make it 2 decades before they're entirely extinct.
With that said, I have owned a few calibers that for various reasons are now impossible to find short of handloading my own. One of which, I think is a really good caliber, but the gov't (biden) killed russian imports, so I don't expect to ever see its' full potential in the US. (9x39)
After a quick search online, everything I'm seeing is out of stock too. Mossberg will often do small runs through their product line. If it's still showing on their website, they haven't discontinued it. However, when they do a run of them, probably won't be in as high of numbers as their other more popular calibers. So if you want one and see one, you may want to grab it when you do.
I'd also like to welcome you to the forum. I enjoy shooting with suppressors too.