[If 188 cabs is better than 300, then surely only a single cab would be even better still!]
False dichotomy.  The argument that 300 cabs would actually cause more harm than good does not necessitate that the reverse is true.  It also doesn't help your argument that you misunderstand her point.  Her point is that the number of cabs is unrelated to the amount of demand for business.  Your argument about less cabs doesn't refute that point.  While I disagree with some of the conclusions she presents, mainly that fares will go up (as we've seen with this Assembly decision the regulations don't always reflect market factors), she provides information that some may not be aware of.