You have to actively ignore the web's landscape in the past 5-6 years to state something like this.
Lately, major vendors (with Edge, that includes Microsoft) are agreeing on standards, developing them FAST, and the web moves forward faster than it has ever moved. Long gone are the days where your standards can get stopped for multiple years. And vendor prefixes are less prevalent now as features get implemented properly sooner.
You have extra word in your second point. There is norhing mature. If anything webtech rushes implementation of some feature just so the checkbox “we can do it too” is ticked and that’s it.
* Standards based with no single entity or company "owning" it.
* Multiple mature competing implementations.
* Massive support across the industry and a huge ecosystem.