The Internet has long practiced the "just-in-time,"
"solve-only-the-current-problem" style of network engineering. If
we can solve the internet's problems for a few more years by adding
more bandwidth, why do something more complex?
Yeah, OSI/ISO, IPV6, ATM/MPLS etc solve several problems the Internet
doesn't have yet. But until that time, gun the engine and ram the
envelope. It may not be elegant, but it gets today's job done.