and of course there are all kinds of great tires suited for touring in much narrower widths, lighter etc that will make the bike faster and feel more nimble.
Completely true.
There's a lot of good tires out there. The problem that presents itself to those that haven't researched tires extensively (or spent hundreds of dollars trying different tires, or toured for decades which offers time to try different tires or learned which tires to purchase directly from other touring people)...is there are A LOT of tires available. Which ones to choose from a sea of potential tires? Add in the additional variables within a tire model of extra flat resistance(the "plus" versions adding tons of weight and significantly degrading performance) or widths and a person could easily buy the wrong tire.
Reminds me of the adage, "Many people know what needs to be done, significantly fewer know what needs to be done....next."
I know you're well versed on good tires to use in various applications. I'm guessing the OP is not so well versed. Few people are interested in spending hundreds of dollars on multiple sets of tires to find out what will work well in their use. Surprisingly few cyclists I run into realize the difference tires make(hard-core roadies aside). So people replying "..there's lots of good tires out there.." is useful, but offers no help in "..what to do next". Knowing there's good tires to be had can't get you to buying one set of the right tires the first time and moving on to other things.
It would be helpful if folks suggested a specific tire(make, model and size/width) and why they think the tires would be good in the application. That's something a person can consider and act on.