I think the crux of the development time arguments is that alternatives (eg Django, Rails) are often monolith projects that let you do everything (database mode

I think the crux of the development time arguments is that alternatives (eg Django, Rails) are often monolith projects that let you do everything (database modelling, controllers and templating) all in a single convenient, well documented and thoroughly battle-tested library. You highlight the daunting prospect of moving to C++. You need to pick half a dozen separate libraries and glue them together. Sure, once you've done that a few times it's pretty quick, but it's a scary prospect for a Django dev who can program in C.