Interesting - the benchmarks prove otherwise - it is as fast as other new solutions. So i think you never actually used it in production at any scale.

If angular 1.5 was OK for thousands of devs over recent years then Polymer that is comparable to ng2 or react is more then enough.

Not to mention that for a world without polymer - some of biggest enterprises in the world are betting on it (and I don't mean just google here).