I think it only makes sense to argue on a case by case basis. Saying one unreasonable practice is ok because there are other unreasonable practices is hardly constructive.
For example there is a fixed limit on available land, therefore it makes sense to regulate its use for the common good. The problem with licensing taxis isn't that they are licensed, it's that the number of licenses is fixed arbitrarily without regard to the actual need for taxis.
So you're saying there is a valid public policy case for limiting the number of taxis, and you just think San Francisco got the number wrong? (For what it's worth: that's what I think too).
For example there is a fixed limit on available land, therefore it makes sense to regulate its use for the common good. The problem with licensing taxis isn't that they are licensed, it's that the number of licenses is fixed arbitrarily without regard to the actual need for taxis.