Determining whether or not a service provider needs a license to deliver service is not a question answerable with a simple yes or no. Many elements must be factored into the decision of whether or not to attempt to obtain a license.
The first decision probably should hinge upon the business case. Service providers must determine if the customer density in an area planned for service will support the additional cost of buying or leasing a license to begin with. Also, are there additional physical considerations such as heavy tree cover, significant building shadow or geographic features that make license-free service much harder to deliver? If so, licensed spectrum may be the only option.
Interference is another consideration. In metropolitan markets, unlicensed band operators, if plentiful, can create a very crowded spectrum environment, making a spectrum license much more attractive. Ultimately, the decision as to whether a license is necessary must hinge on the economics and physical characteristics of the market in question as well as upon the availability of licensed spectrum in the desired market and lastly of course on the availability of working capital.