Or you work on an existing codebase. Most C++ code that I worked on had templates, exceptions, and used the C preprocessor.

I used to have your attitude. This works for many languages, e.g. if you know some of the syntax of Python or Go and the usual stuff from the standard library, you can get pretty far.

If you want to write modern C++, this is not really true. You need to know about const correctness, lifetimes, some templates, etc. Or you cannot deal with most projects or libraries, like Boost, Eigen, etc.

It's like saying you can program Haskell in 2014 without knowing typeclasses, lenses, GADTs, etc. You can write some educational form of Haskell, sure. But many libraries use these.

Sure, but there are a ridiculous number of edge cases which result in undefined behavior -- this is something that cannot be avoided when learning C++. You really need to understand what undefined behavior means and what precautions you need to take to avoid it. (Don't get me wrong, recent standards let you write code that's a lot less likely to run into UB, but you need to learn that from somewhere. You should definitely not be approaching modern C++ as an improved C!)