Hi BruceBanner
Lots of good questions and tough to answer concisely all the factors involved in tone and color reproduction.
Upfront, let me say there is a lot more that goes into a good picture than color gamut and extremely accurate colors. You can have these two conditions and have an awful picture. So over-obsessing on just these two factors is the wrong place to be. Yet in that context here is some info that might help your exploration of the questions you have.
So let me start with a chart that I put together some time back showing my opinion of the trade-offs of the three main color spaces. This may answer some of your questions. Green being best, yellow next best, orange a bit worse and red the worst. Note that none of these three color spaces is overall "best". There are just trade-offs in what you use.
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With proper color management software, images can best be moved from the three editing spaces to viewing in your monitor space.
Monitors come in two flavors these days
a) close to RGB gamut yet not exactly so ideally you have the calibrated and profiled with the appropriate software and device (e.g from Xrite or Datacolor) and use color managed software and OS settings
b) close to Adobe RGB (wide gamut monitors) yet not exactly Adobe RGB so the same caveats in "a" apply here as well
Printers have various range of color gamuts depending on printer, ink, and the paper used. So the gamut can range to be less than sRGB to similar to Adobe RGB in gamut size yet shifted off a ways.
So each printer, ink, paper combination needs its own ICC profile for proper color management. Good prints and paper companies supply these. Many big box print stores will just use sRGB as the assumed color space and print the best they can for that color space.
Now a key factor here is that even if you have your whole workflow totally color managed, you customer may or may not. With the majority of consumer monitors out there still close to sRGB (note wide gamut) and many don't used color managed software, the industry standard for output to Web is sRGB. It will work well for the majority of folks. It will look highly saturated if they have a wide gamut monitor and are not using color managed viewers.
Also, using larger gamuts than sRGB only helps for those images that have a larger gamut than sRGB. That is typically the minority of images yet you have come across them yourself.
So if you are going to use Adobe RGB or ProPhoto RGB, it would be good to have a wide gamut monitor, know Soft Proofing inside and out and then use it for previews, know the options for converting to sRGB and the various available rendering intents and other settings such as Black Point.
So yes, sRGB as the end goal for monitor viewing and printing may can be sufficient and an easier path to take and avoid knowing as much about all the color management issues. Yet it also true that you can get a more colorful print for images that have a wide gamut that you cannot get with sRGB. So its a pick your poison type of situation.
I am sure you will have more questions yet thought this might help you move forward at least to more questions.
Hope it helps
John Wheeler
