On an industry-wide level, yes, the increasing acceptance and availability of the AR15 probably did largely kill off the PCC market.
On a personal level, I am not really fond of the AR, but my pair of Mini-14 rifles, plus the household Winchester '94, displaced my pair of Marlin 1894C lever rifles, and eliminated any practical need for a PCC. My wife and sister-in-law do like their Marlin and Rossi .357 lever rifles, but much as I like the .357 in my revolvers, shoving those little cartridges through a loading gate is neither fun nor efficent, and I would rather fire something longer-range through a rifle. .30-30 cartridges are much handier when loading a lever rifle through a loading gate.
Another factor at play in my personal situation is that I am subject to PD firearms rules 24/7, so off-the-clock SD/HD with a long gun is going to be accomplished with an 870P
shotgun, except under the most exigent circumstances. This would relegate a PCC to being a mere range toy, making it even harder to justify the price of the ones I find interesting.
I did own a PCC in the early 1980s, an Uzi Carbine, which was quite fun, indeed. Someday, I might try to own one again, for nostalgic reasons.