1. Makefiles are for build systems; they are not C++. 2. Even for building C++ - in 2017, there was no need to write bespoke Makefiles, or any Makefiles. You could, and should, have written CMake; and your CMake files would be usable and relevant today.
> Meanwhile my gradle setups have been almost unchanged since that time
... but, typically, with far narrower applicability.
For me, base CMake is pretty easy by now, but I'd rather troubleshoot a makefile than some obscure 3pp CMake module that doesn't do what I want. Plain old makefiles are very hackable for better or worse [1]. It's easy to solve problems with make (in bespoke ways), and at the same time this is the big issue, causing lots of custom solutions of varying correctness.
[1]: Make is easy the same way C is easy.
Plus - the "obscure third party modules" have been getting less obscure and more standard-ish. In 2017 it was already not bad, today it's better.