It’s an unfortunate reality but why shouldn’t people who are protected be able to take advantage of that? It’s older generations in broad strokes, but also people who were at higher risk, healthcare workers, people who’ve been vaccinated already abroad, etc. It’s not so simple as old vs young and even if it were I don’t see the solution as keeping everyone at a disadvantage because you are bitter that others got vaccinated sooner.
Furthermore, it is possible to take advantage of everything a person with a vaccine pass can do with a (free!) PCR test. It’s even paid for by the government for July and August for travel abroad.
Also, it’s definitely far from certain that some mutation will evaporate all of the progress made. It’s not helpful to speculate like that.