What is involved in becoming a cab driver in Philly? Is it medallion costs, vehicle costs (buying or renting), tests, etc.?

Another example of backlash to Uber/Hailo etc. has been the London black taxis. Their operators study for years for very difficult tests in order to be licensed operators, and pay significant costs in doing so, and as such I can understand why they would be irritated by competition coming in without these conditions, but if these conditions don't exist then it's market protectionism at a cost to the consumer.