You seem to get emotional. Because a guy on the internet does not want to by her GF a diamond ring? Why do you care at all?

Getting married is emotional.

Shouldn't get married.

Getting married is probably something worth getting emotional about. Strangers on the internet having made different decisions (or even thinking badly about my decisions) probably isn't.

you can get married without a diamond ring or a expensive marriage. its only a netloss if you make it one

Ok, fine then...a kid is a net loss, a particularly large one at that. Should you not have kids then?

Kid is a pretty solid long time investment(¹), which makes wife a cofounder. Good cofounder won't ask to burn some money to celebrate foundation of the company:).

(¹) of course some children are still a net loss, but other investments fail too so ¯\_(ツ)_/¯

Your assertion was "if you can afford a $3k MVP you can afford a $3k ring." That the MVP shows a financial return speaks directly to affordability. The parent is not making a claim that financial return is the only thing relevant to decision making.

MBP, of course. Dang autocorrect...