Nice post. I have an LHT but no experience riding a lightweight road bike so I am always wondering. Some day...
I do know that the enjoyment of riding the LHT and the versatility of being able to haul some stuff for commuting, or pick up groceries on the way home, gets me out on the bike more, so that's all good. I also like to be able to pick a rough road on the way home, or charge over sections of gravel or whatever. I guess the bike just fits my style (or lack thereof). :^)