Yeah, even the Jap bikes that are normally indestructible don't take to sitting for long periods.
I agree with having to run a Bonnie hard and often to keep it running. I ran mine just about every day and not just a quick start & warm up but took it out for a 25-30 mile ride. As long as I did it was fine (other than the normal oil leaks, loose parts and loss of electric power
) The Norton was the same way, after it sat when the suspension worn it went downhill.
I rode another Buell today, a S3 Thunderbolt, and was fairly impressed with it. The two that have my attention most are Buells and the K Series BMW.