These results are discouraging, if anything.  Sure, you can reflate the pool of antibodies produced right after inoculation.  But that is unsurprising to anyone.  The 2.4-fold decrease in nAb titers for Delta rather than D614G from booster shot sera is comparable to the 2.9-fold decrease originally observed, and the small difference is most parsimoniously explained by vaccinated people having been asymptomatically infected by Delta in the interim.

This paper does nothing to allay fears around OAS(which the authors acknowledge), and demonstrates increased side effects resulting from higher dosages and more shots.

The vaccines remain quite leaky in the real world.  That's a recipe for more virulent strains to be successful.

The use of mass vaccination has put us on a permanent treadmill towards frequent vaccination.  It could be Marek's disease all over again, and it's probably too late to back away from that.  Frequent vaccination will be mandatory for everyone who doesn't want to die.

It's a good business model for Moderna, but not so good for a better world.