Of course... I suspect that BB will have a boost when Piper and Paul retire.. at the same time, they are good... Very good.. so I have no problem with it
Still, building a significant reputation in maybe a season or two (where you still aren't a Country's top team, if LaLa survive any injuries) is not easy either.

They lost a bit of momentum at the end of last season when they just managed to hang on to a podium finish at Jr Worlds, and throughout this season, as they had less competition opportunities than some of the same gen teams that moved up at the same time (Mrazeks and Lim/Quan, in particular), picking that back up isn't guaranteed in skating.
Yes but I am thinking that if Fabbri/Ayer get to go to worlds it is because Lala and FBS are out. So that moves others up a couple spots.
It moves most teams up two spots. Even that would be very tight for C/P based on current SB scores, which would then have them in 11th (and yes, of course, SB scores are not the end all be all of skating, some teams fall or get injured, others polish their performances and have their best skates of the season at Worlds).
Teams are very close in scoring potential this year, and anything could happen, but I wouldn't be surprised if only one or at most two of the US teams place in the top 10.
And, should anyone have forgotten or never stumbled across this information, there will not be any judges from the USA or Canada on the Ice Dance panel at Worlds. France, Finland and Lithuania will have no interest in scoring the Americans particularly favourably when their (2nd in France's case) teams too are wanting to place in the top 10.