You realise Arrivabene was replaced in like, January, meaning the concept for this car and almost everything made for this season was nearly finished before Binotto took over? In general they'll start some work on the next years car pretty much start of the season, they'll be finishing the major design points towards the end of the season and be building the car over winter while working on further upgrades and tweaks for it.
All the strategy calls, though many were completely overplayed, were under Arrivabene's watch. In general a new guy takes over, takes a few months, analyses what he wants to change and starts making those changes. He only just started reorganising the technical structure which I believe was said to be giving individual departments a bit more autonomy and leadership, etc.
If Binotto is good or not pretty much starts showing up next year or even the year after. If he's started headhunting people he wants then those can take time to bring in, starting in Jan then he won't have had a chance to make many or really any senior engineering changes before the season is over and they'll be pretty late for working on next years car.
Also on top of that Ferrari were so competitive in 2017 and 18 primarily due to the massive headstart they had from unlimiting testing in 2015. Again I'll say either they wasted time spending all that time testing a dead end 2016 concept, or they spent all that time coming up with the best 2017 car they could. They made a HUGE leap forward on chassis between 2016 and 2017 and were for me around equally as good as Merc over those two seasons.
Either way it's WAY too early to be blaming Binotto for this year's car or lack of changes at Ferrari. Bosses at teams take time to make and implement changes and most of this car was designed and built with Arrivabene calling the shots and having had the same several years himself to make the personnel/structure changes he wanted.
