C++ does provide tools to build scalable software, and was already doing so in 1998 (few new features on this front since 98 I guess? Maybe modules, but using them for portable development in 2022 looks difficult given their state in compilers that aren't MSVC). I don't think this is a reason to prefer C++ over Rust (if anything, the tools for encapsulation and modularization provided by C++ are way less convenient and efficient than Rust's--speaking from experience of C++14 and Rust here). Also C++ has the massive drawbacks of lacking ADT, forcing headers on users (which is elaborated in the post I believe) and not offering a "safe mode" like Rust does (the tooling is also massively better, but somehow cargo felt like a hindrance to the author of that post, so there's that).
It did surprise me that the author wouldn't elaborate on why C++ was not chosen, when her argument made it look like it could provide some of the advantages she found in Rust. However, she doesn't *have to* elaborate on every possible subject in that post, and implying she doesn't know the language (anymore) because of her not focusing on the reasons she didn't use it looks like a dubious stretch.