There is a need for better image formats for photography, for gigatextures, for voxels, for specialized cases, but not for general web use. This problem is solved. Move along.
ASCII has served us well, it's still used now, and even though it's broken in a lot of ways, UTF-8 addresses most of those to a degree that's satisfactory enough we don't need people inventing new character encoding systems.
Between GIF, PNG and JPEG you have what you need. Don't cry over a few wasted bytes or a few smudgy pixels.
And it's not like JPEG or ASCII or UTF-8 or anything we use today is going to suddenly disappear if we add new browser support. Why not strive for excellence?
FWIW I disagree strongly with his sentiment.
It may be X% smaller than JPEG for the same image quality, but does that really matter?
If the bandwidth cost saved is greater than the cost of adding WebP to Chrome, then it's a net win. Or if it makes some Google page load 10 ms faster, that would also pay for it.
years before you can rely on all your clients having WebP support.
That's what content negotiation is for.
Majority of the mobile phones will only have access to 2G/3G speeds.
In a lot of countries, mobile data is metered. Saved bytes = saved money.
So, yes, it does really matter