If they actually get to 90% or more, why would anyone bother with the more expensive and cumbersome vaccines? Except that the EU already signed a deal to buy the vaccines from AstraZeneca, Sanofi and Johnson & Johnson.
Additionally, lots of countries have already preordered all the major candidates, so in those cases its already spent money.
It isn't a new thing for what it's worth. Going back to earlier this year it has been looked at, but we don't really have a clear picture on what will shake out.
We need the vaccine to remove the virus from circulation, not just keep us safe from it as individuals.