First, I would like to dissociate myself and my  opinions from Vue/e-on bashers like Cobraeye.
If I thought Vue was a horrible product and e-on people are monsters I just wouldnt buy the  product  and wouldnt come to this forum. Nobody is forcing anyone to buy vue. It is because I love vue 6, (and even vue 7complete  which is still riddled with bugs) that I'm trying to sort out issues I think are wrong.
I have been treated courteousely by the e-on staff both in tickets and by phone. Bug reports are answered quickly and most of those I reported were fixed quickly ( although they didnt make it to the latest update). However, with respect to the complete->infinite subject I get no real response. Politeness should not be confused with helpfulness...
Gareee:
"Personally, I do agree with you.. there's no good reason I can think of not to allow a sidegrade from 7.xxx to 7.xxx, BUT if eon can't cancel an activated 7.xxx license, then it WOULD make sense.. then a customer would have both a valid complete and a valid infinite license, which they do not permit."
I'm glad that once you understood my point you agree with me about the principle. Excellent. The technical issue of a license is not relevant. They dont claim its an issue and in fact they agreed that I could 'return'  V7c even after a month and get a (too-small) discount on getting V7i.   So they are not bothered by me having first a liscence for complete and than for infinite. Even if there was a problem, they are capable of solving it. They managed it with Esprit->complete upgrades they could manage it with Complete->inf upgrades. You give their abilities too little credit.
Rids:
"Personally I think they are purposely trying to create a two tier system so they can charge outlandish prices for Inf and Xstream in the future"
Spedler:
"To get away from that hobbyist label, the obvious approach is to have one line for the pros and one for everyone else....and to allow upgrades from one to the other is blurring that distinction."

I dont see anything wrong with having distinct artist &pro lines, it just should be possible to move from one to the other.
E-on may well have a hidden agenda they would prefer not to talk about, but users/potential users
dont have to assist them in keeping it secret. That is  why I am not letting the issue drop, and why I started this thread. I'm putting to them a clear question and I want a clear answer -  I think I and other users deserve one. I'll do all I can to get one.
 It is a matter of principle.
In fact, I do not  want at the moment to upgrade  from complete to infinite. But I would like to have the option to do so in the future if circumstances change.

"I paint that which comes from the imagination or from dreams, or from an unconscious drive. I photograph the things that I do not wish to paint, the things which already have an existence."
Man Ray, modernist painter
http://artpearl.redbubble.com/