AK building is slowly going away. Plenty kits and barrels available. As for AK rifles, there are lots of different models available frome Arms of America and Atlantic firearms.
I believe the 7.62x39 will be around for some time. I dumped my 5.45 and 54r stuff long ago. Check out the galil ace, it can scratch the ak itch and you can easily mount optics and suppressors.