I don't see that the IETF in its present form has much more to contribute: it has no official status and the interested parties have no dependence on it for their continued collaboration
That must surely come as a surprise to the likes of Cisco, Google, Juniper, Huawei, Akamai, Microsoft, Cloudflare, Nokia, Apple, Ericsson, etc who are heavily invested in the IETF and its outcomes.
If the IETF hasn't got "much more to contribute", where do you propose the work on core Internet protocols (routing, DNS, HTTPS, TLS, etc) should get done? Do you want this stuff happening behind closed doors at the ITU or 3GPP or in some banana republic's Ministry of Stupid?
If you're a group of predominantly Chinese firms wanting to come up with a uniform approach to a technical problem what value does the IETF provide?
Technical/engineering scrutiny by subject matter experts who have experience and insights into what does and doesn't work.