Plenty of reasons why.Why?
1). UAE is already full of one dimensional riders. They are full of climbers and time trialists, never a combination of the two in the form of a rouleur. Which, of course, were the type of riders that made Sky the pinnacle for a decade straight and which sets Jumbo apart from the rest currently. Kung and Van Baarle were on the market this summer, but instead they opted to throw big money at initially Quintana and now Yates. Two riders with a profile they have plenty of already.
2). There are plenty of question marks surrounding UAE and its cohesion and team work as it is. They're already much of a meme in the cycling world currently. Their answer to those problems is to sign another leader? Oh, to be a fly on the wall during their meetings.
3). Why would you sign Almeida with big bucks for 5(!) years if you're going after another B-tier GC rider the summer after, allegedly with room to lead in stage races? Doesn't really look like there's any thought and vision put into these signings.