Do you have some numbers?
As far as I know, it indeed supresses the virus from circulating, it just doesn't stop it completely.
Here in my area, which started early with broad vaccinations - the numbers are way down.
https://ourworldindata.org/explorers/coronavirus-data-explor...
For fun, add India, which has comparatively low vaccinations, where Delta began:
https://ourworldindata.org/explorers/coronavirus-data-explor...
But while I was looking into that, last at the beginning of the year - the quality was horrible. Even here in developed germany, it was hard to get meaningful numbers from different districts. I mean, there were lots and lots of data flying around, but most of it not solid or directly comparable in my understanding.
And here india looks interesting, if true. That would speak for a sort of herd immunity?
I think most data is not really comparable across countries, only across time (and even then: discard data early on), because of different levels of data collection. So best only to compare the same country vs its own prev spikes. But this is esp true with India vs smaller countries, you may be able to compare Euro nations to each other more accurately, but would caution against interpreting small differences as meaningful.
UK for instance: https://coronavirus.data.gov.uk/details/cases
Both those factors would result in a softer curve without any vaccination.
Hospitalisation rates have been pretty much flat vs previous waves (there was no wave last summer).