Can so many venues fill all their seats?

Very much related to the question of whether Philadelphia can support what it has built is a rising doubt that there are audiences large enough to patronize all the performances now happening in these larger and more numerous venues. The argument advanced by planners of the Kimmel Center during the preopening fund-raising phase was that relative to other cities, Philadelphia had fewer seats.

The Kimmel's main tenant, the Philadelphia Orchestra, saw the expected boost after the opening of Verizon Hall, but attendance since has dropped sharply. The first season of a new music director usually creates a substantial bounce in ticket sales, but Yannick Nézet-Séguin's arrival in 2012 moved the percentage of the house sold only a hair, to 84 percent from 83 percent. Pennsylvania Ballet ticket sales have been flat for a decade. The 2007 opening of the Perelman annex to the Philadelphia Museum of Art did not boost overall Art Museum attendance.

Is the city oversupplied with arts and culture? Or do groups lack the marketing sophistication to lure audiences? A recently commissioned Opera Philadelphia study unmasks an insidious trend: The traditional subscriber model is declining each year, which means that, without changes, the company eventually will end up with a decline in total ticket sales.

And yet, for now at least, more people are seeing opera. In other words, the problem isn't attracting new listeners; the problem is keeping them. "We don't think the new buyer is a serial buyer, and we don't think they are going to be," says general director David Devan. "They'll pay more money for their ticket, they want a full-on experience, and they may never come back."

The phenomenon has implications for philanthropy, since the most generous donors are those who also attend. Opera Philadelphia has identified a kind of fan who, instead of buying two $44 or $153 tickets five times a year, might listen to a broadcast, attend family day at the Academy of Music, and sit for a concert on Independence Mall - all free.

Both kinds of fans must be tracked and cultivated as donors, Devan said, but "we're totally not set up for that. If we hold on to the subscriber model and only cultivate people who come into the opera house, we're really in trouble."

- Peter Dobrin