Not convinced that governments should be getting into this sort of stuff.
Philosophically, I do believe the government has an obligation to protect citizens from unethical business practices. Expiring gift cards - or gift cards with fees - should be outright illegal. Miles are a gray area...it gets into the whole "are miles an asset owned by the flier?" question that is often asked with respect to taxes, ownership, program changes, net worth, divorce, death, and other topics.
In practice, as an FTer who plays this game well and directly benefits when other people fail to use their miles optimally (or at all), I accept that mileage expiry works in my favor. In general, I believe it has worked to my advantage for 20+ years that miles are not an asset. I believe this is true for anyone who likes to redeem miles for long-haul J/F where the airlines are (usually) careful to firewall off the paid seats for corporate purchasers.
That said, I can totally see why someone not sharing our "expert user" perspective would want to argue that miles are a currency, a coupon, a promise, an asset, or something else owned by the flier.