The average age of a gamer is 33 years.
Most games on non-Nintendo consoles are better than most Nintendo games.
That I would disagree with. Nintendo-games usually are above average, meaning that more games are worse than better than Nintendo-games. If you would say 'some games on non-Nintendo consoles are better than most Nintendo games', that would be something to agree with. But as every platform has a lot of shovelware the claim as you made it is definitely wrong.
EDIT: Also to comment towards your claim of average age of gamers as 33 (based on what study, which games are included - smartphones games often have an adult audience), some simple questions to ask are: what is the median age and how many of the gamers are kids. Because you see, an average can be misleading. In the case of ages - no one can be below 0 years old and mostly very small kids can do activities like gaming at all. As an example: if game A is played by 10 ten-year-olds and 5 eighty-year-olds the average age of the gamers is 33, but that doesn't mean the game is played mostly by adults.