Which statement? All major browsers can work with it. Apache and nginx, at least can also work with it (encompassing 85% of all internet servers).
That users aren't connecting to http/2 web sites is no indicator that http/2 is not available.
That users aren't connecting to http/2 web sites is no indicator that http/2 is not available.
If 47% of all CloudFlare users are not connecting via HTTP/2 (even though it is supported server side), I believe it means that those users do not have client side support (or are behind a proxy, etc. which doesn't allow it).
At the end, if someone is thinking about making a website which would be much slower for non-HTTP/2 users then right now it means around 47% of their users.