Is modern C++ becoming more prevalent?

Absolutely yes. To me if you're not programming C++ in this "Modern C++" style as you term, then there's no point using C++! You might as well just use C. "Modern C++" should be the only way C++ is ever programmed in my opinion, and I would expect that everyone who uses C++ and has programmed in this "Modern" fashion would agree with me. In fact, I am always completely shocked when I hear of a C++ programmer who is unaware of things such as an auto_ptr or a ptr_vector. As far as I'm concerned, those ideas are basic and fundamental to C++, and so I couldn't imagine it any other way.

In the days of Windows 3.1, C was the standard. When C++ hit the developer market and later became ANSI standard, it was the new hotness. It popularized the OOP acronym and some of the basic design patterns using polymorphism.

Now, with the greater acceptance of low-barrier-to-entry managed platforms, like C#/.NET, there's less of a reason to use C++. So much of the developer base will have a choice and let's be honest: C++ is a bear to learn for a novice. With C#, you can just run with it.

That leaves really only the platforms that NEED C++ and the die-hard C++ evangelists to continue practicing the art. This is the community that needs and wants all the layers of abstraction that is considered "Modern C++".

So yes, I believe "Modern C++", as you state it, is becoming more prevalent. Albeit, it's prevalent with a different audience than has used it in the past.

Here's how I think things have evolved.

The first generation of C++ programmers were C programmers, who were in fact using C++ as C with classes. Plus, the STL wasn't in place yet, so that's what C++ essentially was.

When the STL came out, that advanced things, but most of the people writing books, putting together curricula, and teaching classes had learned C first, then that extra C++ stuff, so the second generation learned from that perspective. As another answer noted, if you're comfortable writing regular for loops, changing to use std::for_each doesn't buy you much except the warm fuzzy feeling that you're doing things the "modern" way.

Now, we have instructors and book writers who have been using the whole of C++, and getting their instructions from that perspective, such as Koenig & Moo's Accelerated C++ and Stroustrup's new textbook. So we don't learn char* then std::strings.

It's an interesting lesson in how long it takes for "legacy" methods to be replaced, especially when they have a track record of effectiveness.

I am one of these guys who learned how to work with the STL and heard a lot about RAII and good C++ programming practices from day 1. Looks like some of the most recommended books for learning C++ today (like Accelerated C++ and the Effective C++ series) focus on using STL tools instead of rolling up your own stuff, and also give lots of "rules" for effective (or "modern") programming.

But talking with friends I also noted some companies still work with "C with Classes", not "Modern C++". Maybe the culture proposed by the authors and users of the "Modern C++" will prevail someday :)