It’s the same as with Linux, GIMP, LibreOffice or OnlyOffice. Some people are so used to their routines that they expect everything to work the same and get easily pissed when not.
Open source software is quite far from behind the curve.
There is almost no-one in my field in academia not using R and Latex. Combining it with Linux makes my life much easier.
Wikipedia is open source. Firefox. Chromium. WebKit. Android. Immagine your digital life without any of those.
Whenever I’m forced to use proprietary software I feel like I’m being held back. I know it’s mostly just a question of what you’re used to, but saying that open source is behind the curve is just not accurate.