I'm a GIS Analyst for a county government (not Cook County) who is steadily moving towards GIS/back-end developer. I've gone from just making maps and datasets as a tech to analysis and model building to web development with GIS, (linux) server stacks for db, and more.
I have access and experience using ESRI, but I have completely moved away from ESRI products for my day-to-day, using exclusively open source software. That is, unless something forces me to use ESRI for compatibility/sharability's sake.
I hope to one day develop for QGIS or some other open source software that focuses on GIS, web development, and/or back-end development.