I work for a company that integrates very tightly with Esri (https://www.esri.com), which has the largest market share of any GIS company (over 40%). We use their JavaScript SDKs for our web-based maps, integrate with their online spatial analysis APIs...the works. This is all great, but many of their offerings get very expensive quickly. Most prices aren't even available to see on their site without an account.

I haven't used QGIS beyond downloading it and playing around, but I'm glad to see FOSS solutions in this space.