I develop mostly Python for a living, so I'm well aware of this problem. :)

Like all rules, this has exceptions. This is sort of a good "exception that proves the rule". Yes, PEP8 compliant Python development requires you make a few-line change to your .vimrc. My .vimrc contains this:

    " Set tabs to width 2.
    filetype plugin indent on
    set shiftwidth=2
    set softtabstop=2
    set tabstop=2
    set expandtab

    " language-specific settings: tab width is 4 for python
    autocmd FileType python setlocal shiftwidth=4 softtabstop=4 tabstop=4

So sure, not completely default. But note: the 8 line change I have works without any other changes on every vim install I've come across, and doesn't really change my behavior as a user that much. The people I'm arguing against are proposing installing whole giant behavior-changing plugins (i.e. a linter). I've got a few changes in my .vimrc, but probably fewer lines than even the most basic plugins.