It is nice to lie down on the beds and get a sense of what you want. We went to a store for our son's mattress, but when it was time for our daughter to move out of the crib I made phone calls to a couple of big mattress suppliers. They purposefully have things like a Sleepy's specific model that only lasts a year, to make comparison shopping nearly impossible. On the phone they'll map a previous model to the current model for that year (and the big ones can do the same thing across competitors). Its much easier to call two different companies in the span of 30 minutes, when you know what you want already and get a better price than you would in the store, with less time and hassle.

It's roughly because of the inordinate amount of value we derive from furniture (so people aren't all that price sensitive).

I definitely want to try a mattress and see how it feels before I buy it. Especially if it's going to cost a lot of money.

Stores, I'd argue to physically try the mattress.

Salesmen, absolutely no reason.