Yes and no: The bottling lines don’t get replaced, and in fact the EU checked beforehand that they won’t need to be replaced because otherwise the whole thing might’ve been an undue burden on the industry and they would have to make a closer evaluation, give the industry more time to switch, etc. The new caps can be screwed on by the old machines and if not, only cheap parts need replacing.

OTOH bottle cap manufacturers very much did do their homework, or at least the ones producing good caps that beverage companies will buy did it as no beverage company wants to be the one with the awkward caps. That’s not to say that there’s not bad designs out there but those will vanish. Also some consumers seem to have skill issues, like not latching the cap into the open position.