The fact that it originated in Google doesn't make it some kind of proprietary protocol. It's subject to the usual IETF process, just like others, and is a public draft: https://tools.ietf.org/html/draft-ietf-quic-transport-22
Under these sorts of arrangements, standards bodies have little choice but to rubber stamp the company's interests or face irrelevance. On the HTML/JS side, we often see the same problem with the W3C.
The web's baseline protocols are slowly being replaced by protocols designed to favor the interests of a single company without enough meaningful checks on that. I do not really think it's an IETF/W3C problem though, so much as a economic power one.
The important point is not to make proprietary deviations to the standard. Of course, Google is guilty here (Chrome-only web service, mostly) but when it comes to network protocols they haven't behaved badly, especially when others were pushing for HTTP/2 without TLS and other harmful ideas...
The chrome argument at least sort of makes sense, but I really don't get how the network transport that literally no one but Google can see threatens IETF irrelevance.
I agree with you that how Google servers talk amongst themselves has no relevance in Internet standards.
It's actual normal for Standards Organizations to look like this. If anything by their standards the W3C is very liberal. ISO's members are UN member states for example. Want a delegation to ISO to disagree with how an ISO standard works? Create a sovereign entity, seize control over an appreciable amount of the world and force other sovereign entities to accept you as an equal or you can't. The SI units are controlled by Conférence Générale des Poids et Mesures which only has countries as members - some countries don't even get full membership. Don't like the kilogram? Unless you are literally a country too bad.
The IETF is the far outlier, it might even question whether it is indeed a Standards Organization at all. After all it doesn't have any members, (the Internet Society has members but the IETF does not) and so perhaps its "standards" are only "standard" the way English is standard: a bunch of loose conventions, some honoured more consistently than others. Nobody pretends there's a "Standards Organization" for English after all.
I mean... are you though? Because this feels like if somebody told me they are aware there are "some changes" between "Nothing Lasts Forever" and "Die Hard". I mean, yeah, "some" -- like the "hero" cop is actually a hero because Bruce Willis didn't want to play a washed-up alcoholic nutjob whose paranoid fantasies come true... Wait that's a pretty different story isn't it?
Google was welcome to not use IETF protocols before (and sometimes they didn't) and it'll be welcome to not use IETF protocols afterwards (and likely sometimes they won't).
The IETF has no enforcement arm, it exists so that people can agree on things they all want to do. Or, they don't agree on what to do and then they do whatever they want. Lots of people want a better TCP with encryption, enhanced privacy, a way to avoid head-of-line blocking and a fold-away double bed and the QUIC working group has, starting with Google's experiment over two dozen drafts ago, been trying to build one. Some of its participant are from Google (which is great, they have some really smart guys) and of course most are not. You can and should contribute.