It is the 2% Market Share that MUST be used to evaluate transit and here is why:
Despite the huge increase in the amount of transit over this period, market share is 2% because  transit cannot cater to the chosen mode of development throughout the country  -SPRAWL. There will never be "A better measure of transit's effectiveness:- transit competitive trips" simply because transit can never compete in the many suburbs and no one will go/carry their shopping on the bus or train. Even if, lets say, 1/2 of all miles driven is non-commuting and of the remaining 1/4 is the equivalent of commute driving to/from the Transit Station then we could still allocate no more than 5% market share to transit compared to the remaining competitive commute-miles driven.As to the other "myths" we need to look at the Data.
"Myth" 3: Commuting by rail is slower than commuting by car or bus. TWELVE ANTI-TRANSIT MYTHS: fails to prove that a transit commute, with the average interconnection time, is any faster.
"Myth" 4: Transit does not relieve congestion.  Quoting the St Louis Police Chief is hardly a scientific argument. Here are the St Louis FACTSand the Induced Traffic argument rebuttal. Also the data says a Freeway lane has a capacity of 5,000 vehicles per hour not 1,500. Where transit is serving large Metropolitan areas with a market share far greater than 2% then it makes a difference, but nationwide, at 2% overall average, it can make little difference to congestion.
Reference to the "Myths" can also be found here Transit Referenda and Why They Succeed or Fail

US Urban Personal Vehicle & Public Transport Market Share