When will we ever hear turntables demoed fairly?

To my amazement after 45years we still have no way of ascertaining the sound of turntable designs.Every stereo store has tables set up with different arms and different cartridges.How then is anyone to determine what is contributing to the sound when an apple is being compared to an orange and then to a pear.It's absurd and to make matters worse you are listening to different phono stages and amps and and speakers.If you can't isolate what is contributing to what what's the point.End of rant.