C++ was not simple 20 years ago! We had template metaprogramming, and regular arguments about what subset of the language we could all agree on to safely use. Nobody understood it all even back then.
Right. There were even regular puzzle columns in magazines where people had to figure out what a piece of C++ actually did. This is how template metaprogramming eventually came to light, when a few very clever minds figured out how to use it to implement even conditions and loops, for example - possibilities that even the inventor of the language had not anticipated. So, C++98 was in no way simple, but definitively much more simple than C++ today.