Tinker
That would have to have been a bad fit or something if so.
I used a 9* 455 for many years and it was as long or longer than anything produced over that time. The only driver that i hit longer was the Ashton E3 Speeder 651 combo, but I wasnt quite as consistent due to the light shaft. Geek DCT was equally good to the 455. Only hit the Indio once when Accuflex owner , Jody, set up his trackman at a range at an FGI tourney, it was decent but not for me looks wise and too long heel- toe.
Modern day drivers have the advantage of better shaft technology and better fitting technology to match shafts to our needs than we had back 14 or so years ago when the 455 came out. We can also fine tune swingweight and loft pretty easily so dialing a club in is easier to do with modern heads. If there are distance gains achieved that is probably why. Ball technology and ball fitting has also improved in the past 14 years . I can hit My Ping G25 and Ping G as far as i hit my 455 ( just not as consistently often) even though I'm more than a decade older . They are a bit more forgiving heads which helps but in comparing the heads themselves , it's probably not that the driver heads are any longer but the advances in technology and fitting that contribute to distance gains, if that is what people find.