While you may have never bought a holster from a local store, my point was that the option is far more available for right-handed people than for southpaws. Trust me; I've looked at what's available locally, from a left-handed's point of view.
I can't imagine anyone disputing that, or arguing that "availability and delivery times" of online sellers will rival those of a local store that has what you want in stock. While the holster you bought from Top Gun Supply could simply be returned to that store should you have decided you didn't care for it, you still had to wait to receive it.
I believe you may misunderstand the point I'm arguing.
Let me clarify - my argument is not that there are the same number of lefty holsters at the local gun store/sporting goods store/hardware store/etc. I agree with you there are typically more righty holsters at the local store than there are lefty holsters. I have no argument with that, and never did.
My argument is the odds of finding, what the OP is looking for - "a good IWB leather holster" - at the local gun store/sporting goods/hardware store/etc., is very unlikely. If you want an Uncle Mikes nylon holster, or BlackHawk SERPA, or maybe a soft leather Tagua, DeSantis, or Galco, sure, a righty may find one of those economy holsters on the shelf, and there may not be one for a lefty.
My point is quality leather holsters are typically not found on the shelves at the local store. Unless you are at a special shop of some kind or you find a used holster, none of the holster products I listed in post #3, will be found in a local gun store. Not that those are the only quality products available, but products in that class are different from what the typical gun store will carry.
If the OP is trying to find a quality holster at the local gun store, for a Beretta PX4, whether he is a lefty or a righty, chances are good he will end up being disappointed. The best holsters are generally not available at the local gun shops and are typically purchased by phone or on-line, whether you are a righty or a lefty.
The point I'm making is if you are looking for a quality leather holster, most folks buy those on-line from the maker, and there is no downside to being a lefty in the purchasing process as there are the same holsters available for the lefty as the righty, and delivery will take the same amount of time.