I would ascribe it to the paradigm shift – C++ was the executor, but the advent of the object-oriented programming was the instigator.
By the time Modula-2 appeared in the mainstream, «C with classes» (later C++) had already been begot, and it brought about a major change in the industry. Modula-2, on the other, delivered useful, but evolutionary and not revolutionary enhancements to the ageing procedural programming paradigm.
