> Sure, there are other uses for the data. But the fact remains that generating it isn't free. And changing the coding in and of itself incurs significant administrative cost, so "we've come this far; we might a well just keep going" isn't really a compelling reason to expand ICD.
The WHO expands and revises ICD all the time - and how it gets used by US health insurance isn’t really a concern of theirs. The WHO has 194 member states and the US is only one of them. WHO intends the ICD to be used for collecting public heath and cause of death statistics, and if some countries want to use it for insurance/billing - that’s their problem, not the WHO’s
The US uses its own modified version of ICD-10, ICD-10-CM, which adds even more codes. A lot of those added US-specific codes exist simply because some hospital - or bureau of vital statistics - somewhere in the US, was tracking that. Other countries have done the same thing - Australia has the ICD-10-AM, Canada the ICD-10-CA, Germany the ICD-10-GM, etc
Just because a code exists doesn’t mean you have to use it for any particular purpose. Indeed, most medical software packages permit disabling codes you don’t want clinicians to be able to use. In an insurance system, a code like Y35.5 is likely marked as non-billable.