“…The broad result of this stream of literature conforms to the general intuitive argument of Tinbergen that the number of policy instruments must be no less than the number of policy targets, except in special cases (Arrow, 1958;Tinbergen, 1952). For example, Katsoulacos and Xepapadeas (1995) argue that social welfare may be enhanced by imposing a license fee on entry in addition 4 The result of insufficient entry, which is caused by business-enhancing competition in the standard models with no network effects, is obtained by Gama and Samano (2021) under business-stealing competition, provided that network effects are strong enough. 5 Perry (1984), Suzumura and Kiyono (1987), Nachbar et al (1998), and Amir and Lambson (2003), to name a few, also demonstrate the inefficiency of free-entry equilibrium in alternative scenarios.…”