Consumption habits are sticky. It's more effective to get a young person to like your product and they'll buy it across their working life than to try and convert someone already loyal to another brand
Not always true, it can backfire hard. I know zero 30 year olds wearing abercrombie, hollister, or american eagle today, although that was literally the only acceptable brands for them 15 years ago. Abercrombie still sprays that cologne in their stores, reminds you of stepping back into highschool or middleschool.