C++ became popular because in the late 80s, 90% of programming was done on the PC. Zortech C++, with the first native compiler, provided the most powerful metal programming language available.

Zortech C++ is what gave C++ critical mass to succeed.

P.S. before ZTC++, the traffic in the usenet C++ newsgroup was neck-and-neck with the objective C newsgroup. After ZTC++ was released, traffic in the C++ newsgroup took off and the objective C one faded away. Borland saw our success, and pivoted away from their nascent attempt at an OOP language towards implementing Borland C++. Microsoft then also abandoned their OOP C project (called C) in favor of developing C++.

(I've never been able to get any information about C, I was just told about it by a Redmondian.)