At $21,000 full up for the top touring model I could buy a farkle up 2 Versys. Heck I could get a top of the line KTM 990 Adventure AND a KLR!
You could say that about everything in life. Why buy that $200,000 house in suburbs when I could by a $50,000 house in the city and a $150,000 house by a lake for the weekends.
Why buy that steak at Ruth Chris steak house when you can go to the grocery store and buy enough steak to through a party.
Why buy a King Ranch crew cab pickup when I can buy a regular cab farm truck and a 4 door sedan.
Why buy a sports car when I can buy two Ford Focus.
By the time you made a Versys equal to the suspension, handling, and features that come with a Multistrada you will have close to $20,000 into it. Have you looked at the cost of full Olhins suspension, ABS, traction control, multiple power settings, etc, etc.
I say, if you have the money and that is the way you want to spend it then go for it.
If you do the math, you wouldn't buy anything that depreciates, you would grow your own veggies, and buy a zero lot line 1000 square foot cottage for your family of four.