You could argue they abandoned that market long before (around the era of the mac pro trashcan). Along with the pro software.
replyThey can abandon it multiple times ;)
replyWhen they introduced the cheese grater Mac Pro the new high end GPUs were a showcase feature of it. Complete with the bespoke "Duo" variants and the special power connector doohickey (MPX iirc?). So I'd consider that an attempt to re-enter that market at least.