The difference being, if you choose to get vaccinated, it’s 100% chance that you get mRNA. If you did not get Covid so far, the chances are going down you ever will.
In many countries, the number of people getting the vaccine has plateaued, and at a fairly low level. Combine that with loosening policies, lower precautions, and more transmissible variants (like the Delta variant), and I think a lot of unvaccinated people may be at higher risk of catching it then they expect.
Once the pandemic phase is over, it'll be yet another endemic disease, meaning that as time goes anyone's chance of getting it tends towards 100%.
Flu is endemic. Many people have never had it. The idea that 100% of people will get not only COVID but the exact strain that exists today does not seem well supported, especially as governments are already making noises about variants and booster shots.