I'm sure it will eventually be completed, the money is still all there - its simply that some of the players became targets in the purge as MbS consolidates his power. They are busy reorganizing duties and monies and I cannot imagine will allow such an iconic tower to become an embarrassment for too long. This whole episode is actually something common throughout history in absolute monarchies. Anyway, Wikipedia has a handy article on the situation:
https://en.m.wikipedia.org/wiki/2017..._Arabian_purge