It's been clear for a long time that even 100% won't make the virus disappear. Yes, back in the early days when we didn't use the greek alphabet yet eradication was a reasonably possible best case outcome (though not really likely, given the transmissibility across species.

Look at how prevalent pre-delta variants are now: no, they have not disappeared because almost everybody had delta, they have disappeared because of vaccine shots combined with moderate (compared to 2020) NPI. A virus strain does not simply disappear because there's a new one in town, it keeps replicating until it runs out of hosts. And virions are certainly not defecting to a newer, more glorious flag (like humans might do)