It is a bit of a misconception. When you think of the transfer payments, and equalization is the best example, they're based on revenues. It's about keeping departments whole from a revenue perspective.
How they decide to spend that revenue is up to the province. Whether it's subsidized child care or something else, that's their jurisdiction. The amount of transfer payments is not based on what they want to spend. It's based on the actual income at their disposal. It isn't based on a certain province having more generous spending programs than another so they get more money. It is based on the revenues available to the province, which are a function of the economy. As you have highlighted, some provinces are better off than others due to the various economic resources they have.
All I would say is that it is revenue based and not expenditure based, and how a province decides to spend that money, whether it's by giving tax breaks or subsidizing child care, it's up to the province.