Why do so many cartoon characters have these?
kinda gives you a feeling of what the family is like I suppose?? like some families are strict or religious? I've never understood it either, it just makes them look as if their only one character
Why does Popeye have them?
Cartoons have simpler designs and less detail when compared to real life people (duh). So if you want to instantly convey the message that the parents are similar or the children are similar to the parents you have them look very similar almost clones.
It isn't necessarily lazy but if you showed this image to a person who has never seen Simpsons or in the very least millhoue's parents they should be able to grasp the idea pretty fast. I written/spoken form having similar speech patterns helps convey the message.
Timmy turner from fairly odd parents did not do this but in the flash forwards where we see Timmy's kids you can see that his kids are 'clones' it bridges the gap and gets the point across asap.
Microchimerism is a thing but it doesn't make the woman look more like her previous partners. It does make developing kids capable of having small amounts of cells from the non-biological father so long as they busted a nut in the biological mother.
Making the parents two clones of the child is just the easiest way to do things. Deciding which of the child's physical traits came from which parent is time that could be spent elsewhere I guess.
They need an easy way to show that they belong together. Like Wiggum and his wife. Both are fat and have similar hair and faces.
Similar problem: 18yo daughter is often much smaller than the mother. It's easier for the audience to get that the big one is the mother.
Well they might be both from Israel.