OK.
All states have a reporting requirement. Some are mandatory some are discretionary. There is precident for pulling a license.
You also have to consider how legislators can EASILY make license forfeiture automatic under impairment rules. Insurance companies can have specific exclusions (as with other criminal acts) which makes a pot head a de facto unlicense driver in a mandatory insurance state.
The other option is to adjust the impairment rules to the point where ANY trace of use will be presumed a violation. You also adjust the testing rules to allow for a test time longer than two house as with DWI/DUI.
Nobody said it's impossible to medical pot grounds for losing a license, so I don't know what point you're trying to make.
Either way, the trend to to say pot means no license, period.
What "trend"?