This is really not true. How do you think people start companies together when they don't have capital? By splitting 50-50 and working on something "for free" on nights and weekends.
But it's not one guy has the idea, one guy does the work. It's two people who have the same vision working together. One might be more technical than the other but the less technical person is still bringing something worth 50%.
It's not even about bringing something worth 50%, you will often find at that early stage even having someone who brings 35% value while working as a team is worth giving 50% stake cause startups are so hard. It's usually down to owning 100% of nothing or 50% of something in those situation.