If people don't understand the importance of vaccines by now, then the government message isn't going to mean much.

The government set a lofty and aggressive target, and will likely end up missing it by a few percentage points or by a few days/weeks. It's not like they'll be 25% short. The risk from Covid will have been greatly reduced even if we only initially hit 70% of eligible people vaccinated and things open up

Hopefully, the stragglers will catch-up shortly after the arbitrary date, or when they see others live healthy lives with the vaccine, or realize they won't be able to do things that vaccinated people can - travel without restrictions, attend large sporting or music events, etc. Or, they see enough other anti-vaxxers in their Facebook group get seriously ill or die off and change their mind.