Although as you said, the virus doesn't do anything intentionally - viruses are not sentient beings. It's just a numbers game - virus mutations occur naturally, and the variants that are more transmissible (i.e. - less lethal and more contagious) eventually become more prevalent, as they have more opportunity to spread than strains that cause severe illness or death. Dead people don't walk around infecting other people. Natural selection, in a nutshell...

At this point it seems clear that SARS-CoV-2 will continue to spread regardless of how many people get vaccinated. At some point, hopefully enough people will have true immunity from naturally-acquired antibodies that we will reach herd immunity and the spread will come to slow crawl, with isolated flare-ups from time to time.