All else equal, it's easier to sell widgets to young people for $X/month each than to middle aged people for $10X/month each or old people for $1000X each.

Someone who wanted to sell widgets equally as much to all people would focus most effort on the first group.

I think it's like the transplant list phenomenon. Give people a list with 200 people and their survival chances, and they will distribute 100 organs to the 100 with the highest chance to live. Give them two lists of 100, they will instead distribute 50 organs to members of each list. I think I saw that here, but don't know the link.

On top of that, the more orders for widgets you get, the lower the cost you can make them at.