Your comment doesn't make sense, in fact, it's just the opposite. Clearing this up makes more time to work on other things, they don't just stop at amps..?
And you don't get a higher quality show because you have to EQ and reset your mic placements per venue, what you DO get is frustrated bands and even more frustrated sound engineers. Overall, it takes time away from sound check and other resources so in the end, you'd less polished show if anything. Thats the way it's always been. This precisely why musicians/bands are traveling with amp/can sims and SS FR monitors.
The perfect scenario for both band and sound engineers is for the band to set up and be able to sound check right away without* the hassles of troubleshooting. Sims/Captures with IR's make that possible. This is common sense. So you'll actually get a better show because more effort is going into tone before hand so that more effort can go into other things later.