Its been great reading this thread, so I owe a thanks to those who've shared their thoughts so far.
Your thoughts got me thinking some more, and looking back over my own history and actions.
I think to a degree, modding is a right of passage. About 7 years ago, I bought a Golf TDI. Awesome gas mileage (50+ mpg) and reliable. Wasn't long before I had upgraded the tires and rims. Then came bigger injectors to up power. Then followed a remapped ECU for even more power, which meant an upgraded clutch, upgraded ball joints and cv joints. Chose not to lower the car, but did replace the struts with upgraded units.
Fast forward to three years ago. Golf is long since sold to a friend, who reports even today its the most reliable car he's ever owned, too, even with all the mods. Still cracks off 50 mpg when he's light in the throttle, etc.
Three years ago I went shopping for a small used car for the seocnd spot int he garage. I recalled autocrossing the Golf back in the day and how fun that was...except that the Golf was NOT, despite my efforts, a sports car. Sure it was faster and handled far better than stock, but it was still a Golf with a heavy diesel engine pushing the front end around in the corners.
So we bought a used BMW Z4. 28,000 miles and $16K. Solid deal and after about a month of driving the car it hits me: you want a sports car? Buy a sports car. You want an economical commuter car that'll cross the continent with friends in tow, buy a Golf TDI. Just don't buy one thinking you can make it both.
Given I'm 40 now, this thinking wasn't really roote din my mind when I started modding the Golf. Thus I think all the modding of vehicles before now were my right of passage - what I had to do to realize I prefer to buy the tool designed fo rthe job. That you need to properly ID the job, then select the correct tool, rather than trying to make any tool fit any job.
There's a company building dual sports from Ducati Monsters. Pricey, but cool for sure. In the end, though, do you actually have a well designed dual sport? Not in my opinion. You have a street bike build to have longer travel suspension, so it can handle some dirt. Still heavy, now tall, and designed more for straffing desert washes than single track. Still, there's a market - heck, I considered one.
It pains me to say this, but I'm starting to think that modifying motor vehicles is starting to look like a younger man's game to me now. ;) I can still appreciate it - its an art form, of sorts. I appreciate those doing it, but find myself on a different path these days. I like adding functional hard parts (steering dampener, side bags, upgraded hand guards, etc.), but I like reliable and quiet. I've always found loud motorcycles obtrusive, annoying and unecessary. I like stock exhausts (but wish they were designed better). I truely wish stock seats were better. Things like exhaust heat melting turn signals simply shouldn't happen.
But when I want more power, I test ride everything in sight and start saving up my pennies for the winner of my own personal test ride shoot out.
In the end, I feel those modifying their bikes help keep the rest of us you to a degree. We've been there. We've dealt with that issue. We've made our choices - time for others to do the same, based on their own needs.