Is this on its way to pushing out the incumbent proprietary solution and becoming the standard a la Blender? Or is this more LibreOffice -it’s there, but missing so much functionality/polish that an expert will immediately find blockers vs the status quo?
I work in the mass appraisal space, and I use QGIS all the time. The professional alternative is ESRI's ArcGIS.
A lot of shops I know (private and public) will use ArcGIS still, but I'm noticing an increasing number of people (particularly younger researchers/analysts) who are exclusively using QGIS.
QGIS is powerful and full featured, but it is admittedly a bit rusty around the edges, especially when working with very large datasets. If they keep working on fixing some of the sharpest edges I think it will go on to have a good future. Just in the past few years I've noticed significant improvement.
In many ways it feels like Blender -- long ignored and dismissed, but slowly but surely improved over time, and then suddenly became quite a big deal.
I think the answer depends on the country: In places where the government uses QGIS it is like Blender. In places where ESRI has a stronghold it is like LibreOffice.
I work at a university and we do a lot of moving data around, inspecting the files and columns, scripting, etc. so we have everyone use QGIS. Governments and other major consumers have open-ended long-term contracts for whatever Esri products they can think of, so those are solid.
For me the real ongoing question is the role of MapBox, MapLibre, to some extent Google Maps API, and other web-first solutions. It's difficult for Esri to connect with the average web developer or researcher who just wants to start with clickable pins on a map.
It is becoming more and more Blender. Europe relies on it more than Americans, but most GIS specialists use both this and ESRI.
Probably closer to the first situation. It curb stomped ArcGIS in the geographic information system community. When I started working with GIS at work, expensive ESRI products were default in this market, a la matlab in another field. Most coleages of mine had not heard about QGIS. Now QGIS is ubiquitous. It did to ArcGIS and its countless paid add on modules what scipy/numpy did to matlab.
LibreOffice vs Office 365/Google Drive is probably the more relevant comparison.
I won’t comment on market share, but even if theoretically QGIS totally displaced ArcGIS Pro/ArcMap/ArcGIS on the desktop, the arena of competition has shifted to ArcGIS Online and its competitors. And once you’re in ArcGIS Online, Pro becomes the convenient choice for desktop editing.
LibreOffice could be miles better than Office on desktop, but the competition is lost because Office on desktop is just an accessory for Office 365 (which competes with Google Docs/Drive).
Disclosure: I work at Esri.