I think one has to remember there is always someone that wants more options to choose from. They want the Complete Splat book replacements done in Pathfinder rules. I still see requests all the time on the Paizo boards for various rule areas - epic, psionics, etc.
Yup. It's a fundamental part of what makes rpgs what they are today.
It is still your game - if you do not feel comfortable adding more material at the rate it comes out then that is a viable choice and option.
There's a flip side to that though...
I've seen criticism leveled at the Pathfinder game, where the immediate response by fans is, "Oh, you need to by the APG. It takes care of all [whatever]".
As well, people get a little... grumpy.... about the whole banning things. Sure, you as a GM are allowed to ban something. But if you do and later you complain about some aspect of the game, you're going to get jumped with "Well, if you were actually willing to buy [whatever], it'd solve your problem. It's your own fault." and there's a pretty strong implication that you should just shut the heck up.
What I'm saying is that sure... in _theory_ you've got the right to ignore/ban something. But the practical reality is that by doing so, you're basically cutting yourself off from a decent chunk of the community; a community which feels people _should_ be going out and buying all the options, because _someone_ is going to want them.
I'll just about guarantee that if you come out on the forums and look for help on something and add the stipulation "I will not buy another product", you're going to get basically no help. If you talk about using a 3.x bit of material and how to incorporate it, people are going to tell you not to do so because Pathfinder is so much better balanced and/or that Paizo has that covered in such-and-such (out or coming out) product.
This isn't an anti-Paizo thread and I'm not making an anti-Paizo stand here.
I'm saying that not everyone feels they should have to buy product and that it bothers some people how they might as well have stayed with 3.5 or switched to a whole new system if they happen to suggest skipping buying new product and recycling what they've already got. Or just homebrewing it.
No, I'm not saying that people in this thread are acting that way explicitly; just that it's the sort of thing you see online in general.
This is nothing particularly new. A portion of the consumers want new rulebooks. A portion don't. A portion of consumers feel entitled to use those books they bought, and a portion feels like that's their problem and they don't want to have to allow it.
Consumers vs non-consumers vs reasoned consumers.
All this has happened before, and all of it will happen again. And again. And again. And again. And again. And again. And again. And again. And again. And again. And again.