Many Twin Cities area trees are showing signs of stress this spring. However, in most cases it's too soon to draw major conclusions about their health. Watchful waiting is advisable at this time. The outcome should be apparent a month from now. So long as the branches are supple and tissue under the bark is green, leaves may still develop.

This bulletin explains some of the things that can account for the problem you have described.
http://msue.anr.msu.edu/news/why_are_trees_and_shrubs_so_slow_to_leaf_out_this_spring

By the way,  unless the mulch was very deep it's unlikely that spreading mulch around the tree harmed it.

Thanks. Still nothing developing. Is it likely due to stress it will just stay dormant this year then start growing again next spring?

super bummed as you can imagine. Large beautiful maple in our front yard. 

If no leaves develop this summer, the tree can be considered dead.  Evidence of this will eventually be manifest by dry brittle twigs and branches with no green tissue under the bark.