One other issue with the mRNA vaccines is that they're brand new technology, never before produced in bulk, so except for the vials, most everything is new and we're still climbing the learning curve. The production of DNA using E. Coli isn't new, but everything else is, including how physically fragile the end result is. If you shake a thawed out vial of Pfizer/BioNTech's, you're directed to throw it out, of Moderna's, call them.
And I'd say with the exception of Sanofi/GSK's complete failure with the elderly, and AZ/Oxford's mess, we're getting about the results we should have expected. J&J's ambitious only one dose is not super good, but not bad, on the other hand it's also relatively new technology, which I'm not sure they've ever made in bulk in a hurry. Novavax's 89% is quite fine from a protein plus adjuvant vaccine (Sanofi/GSK's was the same), and uses old technology like Protein Sciences', they should be able to make it quickly, and only requires refrigeration. J&J should be about ready to make a FDA Emergency Use Authorization application, the Phase III US trials for Novavax and J&J's two dose 8 weeks apart are still in progress.
But, yes, in speed to market mRNA is new technology that's very very fast. Moderna literally developed their vaccine candidate over a weekend, although that was based on a lot of their prior work, and others in SARS like coronavirus vaccines. Whereas they had their first batch made in weeks, then had to wait a couple of weeks for the results of sterility tests.