If you are building a system for a fortune 500 with a well defined purpose, that will run for years, your #1 might apply. But if you are building something new

If you are building a system for a fortune 500 with a well defined purpose, that will run for years, your #1 might apply. But if you are building something new that you aren't sure what will become yet, like a startup, I would go with the thing that gets you up running the fastest. This allows you to validate quicker and then perhaps change if the project grows to require it. As for #2, I think that technology is now such a big field that this sort of argument is very rarely valid. NoSQL databases might be so young that there are no db admins with that as their primary field just yet, but that will change soon.