Oh boy, there's a lot worth pulling out of this overview of upcoming web technologies:
[Mid-range Android phones are the] median device that web users have, Apple’s market share in terms of 2019 Q1 sales in the US is 39%, with Samsung at 28%, while the rest is a range of Android devices which sell for between $500 and $50 dollars.
In other words, as Simon says, the single biggest UX impact is the size of JS shipped. Mid-range phones don't just struggle to download large JS packages, they also struggle to process them quickly.
The web is an open and democratic place, when people are forced to use only native apps they have a limited window on the web experience and the knowledge available therein.
Another potential solution is Web Assembly, which (apparently) compiles 20x faster than JS 😲 That could significantly decrease the JS load needed for, say, React by converting process-heavy parts to WASM. That could be a massive gain to the entire web community by one team's efforts:
In this example a single React release could raise the tide of web performance for all React-based websites.
In terms of Google's proposed "slow website" badge, Simon raises some interesting counter points:
Who knows what the workaround techniques will be: loading screens like 1999, screenshots rendered while the page loads in the background, UA sniffing to deliver a faster experience to googlebot.
He also takes aim at Google Analytics trailing behind on key UX features like Real User Measurements (things like largest contentful paint and blocking time). I'm not sure I buy this quite as much, but any (non-invasive) improvements to the metrics that GA provides would be welcome.
Slow sites cost money, and observability helps us to allocate funds to improve performance.