MissA, its not as clear cut as that unfortunately. I googled to find a scientist who disagreed with the lengthening of the gap; found one called Florian Krammer who put forward a realistic possibility that lengthening the gap could mean that people are susceptible to the virus for longer and that could mean that a new, dangerous strain could emerge. But in the same article (in Science) other scientists argued that while this was possible, the chances of that happening were very small in relation to the existing virus continuing to wipe out hundreds of people every day. So, on balance, the dose being delayed is a good thing. All the scientists are good scientists, but many non-scientific people only see the "mutant virus" part and that's enough to set them off on the "bad decision" route.
www.sciencemag.org/news/2021/01/could-too-much-time-between-doses-drive-coronavirus-outwit-vaccines
p.s. - see DaisyMae's comment above. Israeli Coronavirus Tsar says our approach is correct. Fauci's concern is that we don't have enough vaccine doses to get the second one to people after 12 weeks, not with the efficacy.