Should Each Data Store Have Its Own Data Store?

I'm not so sure it's a good idea because now you're adding complexity to your team. Unless you're going to do analytics on the number of blue pixels, it shouldn't be in it. It doesn't make it impossible to do queries across, but it makes it much more difficult. If there's some little glitchy thing about one platform that makes the abstraction difficult to control across multiple abstractions and queries, yeah, it's just not a good idea. I would argue in favor of one relational store. Though a lot of projects would only need one. And one of the criteria for the data store should be is the analytics tool that our company uses able to read that data