My guess would be, that although Twix sponsored the shows then, it was only for that showing, is it fair that they get free sponsorship a decade or so on? Plus there are rights issues, even from the original sponsors themselves, may not want to be associated with a music show that is quite old, demographics and all that. If you paid for something to be associated with your company over 10 years ago, and they just decided to use it again, you may not be at all impressed, and also they may not want to sponsor something they have done once already.