It might also be that Toyota
It might also be that Toyota is, in the end, a highly conservative Japanese company that runs top-down. The Tacoma might never have seen any updates if it weren't for GM re-entering the midsize truck market. As it is, the updates to the Tacoma are very conservative as were the recent updates to the Tacoma.
You're right, though, Toyota at the highest corporate level seems disinterested in pickup trucks as anything but a niche portion of its overall sales.