I'm 54 and have taken a drag or 2 off of about 4 joints in my life. I'm all for removing all mention of marijuana from the law rather than legalizing or decriminalizing both of which leaves the control in the hands of government.
Any long term plan to tax the product will eventually fail due to the fact that it is a weed and will grow anywhere and is easy to dry enough to smoke.
The reason the street price is so high is that it is illegal in most places and for most uses and the price reflects the legal risk rather than the true cost of the product and when the risk is gone the price will be that of common yard weeds, effectively worthless. Any idiot can grow enough for personal use in a couple of pots on a window sill or in the yard.
Alcohol, and to be honest tobacco, on the other hand takes a bit of doing to create with any quality.

And yes, once legal I would be inclined to use once or twice a year.