As a background I'm a physician and I research a lot of related topics daily.

One of the major issues the pharmaceutical industry has run into is that it's getting harder and harder (and more expensive) for them to develop new medications, as most of the "easy" targets for the current model of drug development have already been found. It's for this reason that most of the drugs that come out now are basically just the same drugs as before but slightly tweaked and made out to be better than their predecessors (commonly known as me-too drugs) rather than any signs of general progress.

This general lack of new drugs to be developed has often been cited as the ticking time bomb that will destroy the drug industry.

mRNA vaccines represent a potential solution to this problem because they both make it possible to make a massive number of vaccines to a large number of conditions very easily (especially vaccines targeted towards cancer), but they also make it possible to treat a large number of genetic conditions or defects (ie. cystic fibrosis) by producing functional copies of whatever protein is missing. In effect if mRNA gene therapies are put on the market, they open up a multitrillion dollar market that will keep pharma going for a long long time.

The issue with this approach has bene that there have been major safety issues and concerns about utilizing mRNA gene therapies since their development which have prevented them from ever being used on human subjects.

Hence predictably, a large focus was put on developing mRNA vaccinations for COVID (even though other approaches also worked) and using the emergency nature of the situation to push through the vaccines (which were also the first ones to get on the market).

There are a lot of competing theories about why highly questionable vaccines with highly questionable justifications have been pushed so aggressively by everyone. Many of these are more conspiratorial and thus harder to argue to people. However, while it's debateable if more nefarious motives were at play, the need for opening up the gene therapy market to big pharma cannot possibly be overstated. In the past pharma has been willing to (and able to) do some pretty shady actions to push through products with a 0.01% profit potential of what the gene therapies open up.

My personal opinion is that this is the fundamental reason why the vaccines have been pushed so aggressively by everyone, and any other reason cited was a secondary concern. In addition, I also think this is the most persuasive means to explain the case to ordinary people.