As long as there are people buying golf gear they will be ok, as they do most business these days online. Plus as long as they can offer custom fit it will give customers a reason for being there. Its when manufacturers start offering custom fit with local pro and buy online direct at discount prices that the likes of AG & DG will suffer.
But the difference with that being local Pro's would get something from the CF session. As long as people can afford to play golf, specialist retailers like AG& DG will be fine as their isn't the general market for stores like Asda & Tesco to dip into it. The problems will come when the rest of the economy goes tits up and people can't afford to play golf!
I think as manufacturers increase demo days at clubs which will include being fitted out they will start to lose any uniqueness. Quite a few pro's at clubs already get involved in fitting for specific brands so I don't think their fitting is a strong security.