The difference between Netflix 1080 and 720p is often pretty small, so you might've really just not noticed. They're generally streaming with pretty poor bit-rates
The first time I watched a pirated episode after years of streaming from Netflix was pretty eye opening for me wrt video quality.
Chrome works in 1080p, but has a 1 in something chance of crashing your graphics driver for some reason. After I had to force restart my pc from a black screen for the 3rd time I eventually moved the the desktop app which doesn't have those problems.
I'm pretty sure I watch HD Netflix in Safari. Surely I can't be watching 720p and be deceiving myself?