In the 1980s, when I.M. Pei designed a new wing for the National Gallery of Art in Washington, D.C., architecture critics began to say that museums were the emblematic building type of our age. Some years later, Frank Gehry’s Guggenheim Museum in Bilbao made that old Spanish industrial city, which not one in a 100 art-loving Americans had ever heard of let alone visited, into one of the world’s most popular tourist destinations. Cities across the world now view museums as an economic development tool.

Against this background, the Art Dealers Association of America on Thursday evening convened an all-star panel, “Beyond Bilbao: Museum Architecture in the 21st Century.” The panelists included the architect Daniel Libeskind, who is most famous to New Yorkers as the winner of the World Trade Center competition, but who was famous before that among the cognoscenti for his design for the Jewish Museum in Berlin. He is also the architect of the Denver Art Museum, among other museum projects.

Panelist Glenn Lowry, the director of the Museum of Modern Art, who oversaw that museum’s recent massive expansion, was in the sometimes uncomfortable position of having to defend his building, even to the point of complaining that everyone thinks of himself as an architect and a curator.

The other panelists were Malcolm Rogers, the director of the Museum of Fine Arts, Boston, and overseer of that museum’s expansion by Norman Foster; and the architectural historian Victoria Newhouse, whose influential books include “Towards a New Museum”(1998). The moderator was Paul Goldberger, architecture critic for the New Yorker and dean of the Parsons School of Design.

The discussion took place at the Dahesh Museum, the specialist in 19th-century academic art that has recently relocated from temporary quarters in a Fifth Avenue office building to a space at 580 Madison Avenue at 56th Street that was recently vacated by the I.B.M. Gallery of Science and Art.

It used to be that preservation advocates were most concerned about developers or building owners seeking to demolish or remodel old buildings. Now it’s the progressive design community itself that has grown bored with the old and views every old building as ripe for “parabuilding” – the chi-chi term for brutally and chicly disjunctive add-ons or remodelings.

Nowhere is this tendency more pronounced than in the case of museums.

Museums present unique challenges. One is that there isn’t a major museum around that doesn’t need or want to expand. Most museums are able to exhibit only small percentages of their holdings. Even more imperative is the desperate desire to cash in on the explosive increase in museum going in recent years. The “blockbuster” syndrome necessitates structures that can handle enormous crowds, who wish not merely to look at the art but to drink and dine and shop and hang out.

Related to this is cities’ desire to use museums as economic development tools. The most interesting point made in the discussion, I thought, was when Paul Goldberger noted the symbolism of old industrial structures, like that which now houses Dia: Beacon, becoming museums: In their earlier uses, such buildings were economic engines. Now they are again, though in a very different sort of economy.

Of the panelists, the one who forthrightly – and cheerfully – celebrated the “public square” vision of museums, not as an economic inevitability to which we must acquiesce, but as a positive good, was Mr. Libeskind, the ebullient deconstructivist who could, as another architect recently said, sell ice to the Eskimos.

The other factor in play is that many museums see themselves as cultural trendsetters. (Thus, in 1939 the Museum of Modern Art felt it had to have a building that was itself one of New York’s signal works of Modernist architecture.) This offers to architects a unique opportunity. Seldom does an office-building developer, or a university board, make it part of the program to be “cutting edge.” But museums, especially post-Bilbao, do. No museum, indeed, wants to be left behind. And many of the “starchitects” whose “cutting edge” designs remained on paper (or computer hard drives) for years got their first big breaks with museums. A case in point is Mr. Libeskind.

Left largely unexamined by the panel, alas, was just what does make a good container for fine art. Ms. Newhouse championed Bilbao for its variety of spaces. Yoshio Taniguchi strove with his design for the new MoMA to create spaces and walls that would not “compete” with the artworks. (Mr. Goldberger quoted Mr. Taniguchi’s now famous remark that for enough money he could make the building disappear.)

Mr. Taniguchi’s idea of not competing is the simplistic idea of extreme minimalism. Yet sometimes very elaborate settings, like those at the Frick Collection, can set off artworks in a way plain walls could never do. Granted, such a setting may serve Bellinis and Fragonards, and even classic Modernism, but would hardly do justice to many works of contemporary art.

But that begs the question: Can any architectural setting enhance certain contemporary art? Mr. Goldberger pointed out that Richard Serra has praised Dia:Beacon as an ideal setting for his works, at least.

The real question left unaddressed is that of whether architects any longer even possess the formal means to create sensible museum spaces. Ms. Newhouse claimed that among Bilbao’s variety of spaces were “classic” rectangular galleries, like those of the 19th century, with skylights. She seems to think ornamentation to be extraneous to the “classic” conception. That judgment certainly underscores how far we’ve moved from any “classic” conception of the design of gallery space.

Mr. Goldberger smartly wrapped up by asking the panelists to name their favorite museums. Mr. Libeskind said Sir John Soane’s Museum in London. Mr. Rogers said the Gulbenkian in Lisbon, Mr. Lowry the National Gallery in London. Ms. Newhouse said Herzog & de Meuron’s Schaulager in Basel.

None is a work of “starchitecture.”