If the argument is "we shouldn't use vaccines because of escape variants" then I don't see why we should fear escape variants more than we do any other kind of variants.
If the argument is "we should build up a big inventory of vaccines and infrastructure to deploy them to the population in a very short timespan" then I see some logic to that but it's not at all obvious that the math works out.
Leaky vaccines do change evolutionary pressure and increase the likelihood of escape variants.
For a case study in the worst case outcomes of leaky vaccines, see Marek's disease [1].
It seems like the mRNA vaccines are at least partially leaky, so there have been concerns raised and alarms sounded by researchers.
[1] https://en.wikipedia.org/wiki/Marek%27s_disease