That assumes developer efficiency is what they were optimizing for. If, on the other hand, they were optimizing in a way that attempted to trivialize mobile to drive people to the (more profitable for them) desktop, then then entire experience makes sense from a product perspective.
I based my assessment on Facebook's public statements regarding their choice of technologies, rather than assuming some sort of deep conspiracy.
It's basic organizational politics. Any organization will have difficulty adapting to a completely different platform, and management will attempt to reframe the problem to fit within the bounds of their existing organization.
In this case, a traditionally web-focused organization attempted to co-opt mobile development into their existing organizational hierarchy by reframing the problem. It wasn't until persistent external pressure was applied (user complaint, blatant failure obvious to external management) that they were forced to accede ground.
I tried to put myself in the shoes of a product manager at FB, knowing that revenue from mobile sucks but everybody wants a mobile solution. How could I accomplish both? By not making a fuss when engineering builds what is obviously a substandard app.
What I forgot to take into account is that Facebook isn't really led by product management. Could FB's PMs force a change like that, after development has built it? I don't know.
