Kudos on writing a solid comprehensive article on mapping, the tooling available, and how to do it step by step. (GDAL and everything!) Not an easy task, and I found the format engaging. Great stuff.
It looks like the city of Chicago might be sitting on top of the Socrata API, which allows you to run a distinct - if you are visualizing counts for each tract (or averages and other types of calculations) it would save you the Digital Ocean resources to grab the API counts either on-the-fly or as static files for the tracts in Chicago and render them that way via Leaflet, but obviously this does not allow for quite as novel an analysis as PostGIS offers! (here's the API page that the City of Chicago links to from their page https://dev.socrata.com/docs/functions/#2.1,)