it may very well have been a last minute addition, with the intent to leave expansion to an election issue.

at the provincial level in ontario, we have more of a traditional left-right axis. and, because ontario is what it is, you can expect that most people in the traditional center swing (which includes a lot of low income workers) will support universal pharmacare - if the liberals present it, rather than the ndp. so, the liberals just need to match the ndp to dominate them.

i live on disability, and even if i was merely on welfare i'd still have better drug coverage than a large percentage of wage workers. report after report has called this out for years as irrational and drawn all kinds of conclusions, including presenting it as a disincentive to employment. but, nobody wants to take away drug coverage from people on assistance. 

it's a good start, anyways.

http://globalnews.ca/news/3410017/ontario-budget-2017-families-get-free-prescriptions-drugs-for-children-more-aid-for-students/