This is just factually incorrect. BioNTech had the capability to produce a vaccine on their own, but not at the scale they needed to. Nor would they have been able to handle distribution. Previously they were only producing various mRNA medication at a much smaller scale.
Pfizer was in a better position to run a large-scale study and create new supply chains at the scale that was needed.
The relationship between BioNTech and Pfizer is not unlike the one between an artist and a music label.
Without them, BioNTech might have partnered with some other pharma corp: Merck (the German company, not the US wartime spinoff) is headquartered 30 km from BioNTech, Sanofi has facilities 20km away and there are a few more around the block that have significant experience in both navigating regulatory frameworks and ramping up production.
In such a scenario, maybe they wouldn't provide 60% of EU shipments now (the numbers I have at hands), but "produced nothing" seems to lowball it.
Without BioNTech, Pfizer would have partnered with a different company (Moderna, Novavax, the list goes on..) and produced a vaccine.
I don't mean to understate the value of what BioNTech's research set Pfizer (and the world) up for, but without Pfizer there would be no BioNTech vaccine.