Your options weren't "either use PNG or some other format", but rather "either ignore IE and design things that can use 8-bit alpha thanks to PNG, or don't cons

Your options weren't "either use PNG or some other format", but rather "either ignore IE and design things that can use 8-bit alpha thanks to PNG, or don't consider using possibilities PNG could give you when designing things at all". So yes, you did use PNGs in some areas (illustrations etc.), but anything that would make you think "I'd have to use PNG to do that" meant "no-go because of IE". Which generally means avoiding PNGs. When you add gamma issues on top of that, it was pretty rare to ever use PNGs for web designs if you cared about IE6.