Pokey- Your applesauce detector may be getting a bit over-used on this one!
1-I recognize that the book is dated, and I referred to that.
2-I don't think though that you have yet made a convincing argument for the triple.
3-Provided that the points he made, dispite your protests, have some merit, his argument in the present tense would be stronger not weaker: The rear wheels now have now 9 or more gears-with that gear range why would it still be necessary to add another range with a third ring? Perhaps now should be the time to shelve the third ring, which I agree still had some merit in certain situations when the cog count on the rear was 5 or 6.
4-My undestanding about chain ring wear is that the inside ring would usually have the truer line, and if so the larger would wear quicker, am I wrong?
5-The low gear quoted was 40.5 inches, he goes on to say that you may want to opt for a 44/40 with a 28 for a 38.6 inch gear, or a 46/42 with a 32 for a 35.4 inch gear. The options that he was dealing with were few due to the five or six freewheels, but he was doing this in such a way as to eliminate annoying ( and therefore unlikely to be used) double shifting.
6-We live in a more is better culture. If the manufacturers think that they will be at a disadvantage trying to sell a bike with a double for touring, they make do that even though the math would indicate that it is not necessary with the new cassette range available.
7-Raymond Bridge was writing in response to a situation that existed then: Bikes were coming out with alpine gears 52/40 with 14 to 28 cogs, and being sold to tourers who were going to be carrying a heavy load. The shifting sequence was awful and the high gear went along for the ride (100.3 gear inches.) I do though understand that bikes have changed and that the triple axles are shorter than then, splined may make a difference as well, but the central point remains-why the third ring and the still necessary longer spindle?
8-Proper gear range is important. When I knew even less than I do today I rode to Mexico in a 52/42-14 to 24-47.3 gear inches. Derailleur would not permit a larger cog, including up Look Out Mountain fully loaded. My friend on a 30 zipped past me like I was standing still.
9-The funny thing is I think that we may agree. You mention that you use the shortest spindle that you can get away with, I don't think that you would then rush off to add a triple even for full touing either.