Biggest issue with fittings,imo is that they occur on a simulator off of mats. Many people would probably choose different clubs if they were actually playing them on a course in the context of a real round of golf. That driver that you managed to get a few miles per hour of more than the others in the store won't look nearly as good when you're hitting in the rough all day. Simulators are great, but they can only represent so much of the game. If a manufacturer or retailer could find a way to let you demo clubs and in real environment ( not necessarily a full round) I would be much more inclined to pay for that.
Watch guys like Mark Crossfield on YouTube and then go to the big box stores and tell them what you want to try.
I recently had a paid fitting at PTSS. It was apparent that the fitter was very knowledgeable, but the experience wasn't great because there was a time limit and the only irons available were 7 irons. I at least want to hit a pitching wedge and a 5-iron to understand how the set flows and possibly look at blending sets. Unfortunately, all I was able to do was to hit the 7 iron of the next model up the chain for that manufacturer. That's not the same as hitting two different five irons.
Also, due to time constraints and the fitters presuppositions, only had a few manufacturers to hit. Granted, they were the first ones that I chose, but would have liked to hit some brands I'm less familiar with.