Interesting. I both agree and disagree with you.
Funny, in my opinion MORE buildings should have a retro look. Modern buildings are sterile and soulless. Too much glass and stainless steel.
Modernism is much more diverse than most people think. Also, elegance and soulfulness are not intrinsically tied to architectural style or era per se. They depend on skill (by the architects) and volition (by developers, owners, communities...). Here are two post-war modernist examples:
1.
2.
If you're using "modern" in the sense of recent or contemporary, the point still stands:
3.
Architecture's push for functionalism over aesthetics is one of the many errors of the 21st century. Too many drab, uniform grey buildings are terrible. Appearances are important. Aesthetically pleasing locales revitalize the human spirit.
The hegemony of function over beauty in architecture - aspects that don't have to be at odds with each other per se - is not unique to the 21st century, in fact its heyday is usually associated with the post-war 20th century and very much connected to the economical boom years on both sides of the Iron Curtain.
Seemingly a paradox, this period also saw the realization of one of the most beautiful sports complexes in human history, the Munich Olympic Parc:
4.
Still, shortly thereafter in the West, the prevalent disregard for beauty or "soul" even provoked the advent of Postmodernism with its playful and often ironic use of archaic elements and historic symbolism (but also its own aesthetic problems, which would be another story).
Nowadays things are even more complex, but to make my point (and wrap this up):
Generally speaking, one cannot create beautiful buildings and a beautiful environment for the general public if one doesn't believe in public space.
Public space, however, is inherently non-commercial or it wouldn't be public. That doesn't mean it can't be beneficial to business and commerce, but in itself it has to be non-profit.
When it comes to soulless architecture, the real culprit is therefore a disregard for public space. And present day utilitarian turbo capitalism plays a big unholy role in this, especially in the US.
"Retro" architecture doesn't really address this problem, it just gives you a sedative in the form of a generic but fake "good old times"-feeling. It is a kind of architectural Prozac.
What's more, our ways of using, moving through and communicating in public space have a big impact on how we perceive it and therefore how it's gonna look like. If we move through it mostly in our cars or with our eyes on the cellphone-screen, it's no wonder that our public space is essentially a giant parking lot seamed with bland facades and attention-grabbing billboards.
EDIT: Photo references:
1. Planalto Palace, Brasilia, Brazil, 1958-60 architect: Oscar Niemeyer.
This is not a sports facility but the presidential palace of Brazil. Dimensions and proportions are similar to an arena, though, which is why I chose this example.
2. Ingalls ice rink, Yale university, New Haven, CT, 1953-58; architect: Eero Saarinen
3. New Bordeaux stadium, Bordeaux, France, 2012-2015; architects: Herzog & de Meuron
4. Olympic Parc, Munich, Germany, 1968-72; architects: Behnisch & Partners with Frei Otto (structural engineer) and others.