This is not what the headline is suggesting.

They are advising against boosters for 3 main reasons:

1 - There are still unvaccinated people

2 - The risk/benefit math might weigh poorly with repeated boosters

3 - The signals of wavering immunity may not mean that much anyway.

You have to read the article all the way through.

If boosters (whether expressing original or variant antigens) are ultimately to be used, there will be a need to identify specific circumstances in which the direct and indirect benefits of doing so are, on balance, clearly beneficial.

And from the conclusion

The vaccines that are currently available are safe, effective, and save lives. The limited supply of these vaccines will save the most lives if made available to people who are at appreciable risk of serious disease and have not yet received any vaccine. Even if some gain can ultimately be obtained from boosting, it will not outweigh the benefits of providing initial protection to the unvaccinated.