The meme coins don't even have idea behind them. They are doing well because the community is supporting them. We can say the idea of Shiba inu is to kill dodge coin. Is that a real idea behind a coin. The meme coin depend on the community. Buy when there is hype and sell no more hype.
There's an idea behind it because saying alone that their coin can kill the other coin is not enough but they have also created an interesting feature to make it possible. Many people will invest on them over the other coin because they like it more better and that is how they defeat their competitor however there are coins that no matter how good they are, they cant still shake the other coin.
See what are happening with bitcoin and ethereum? where ethereum has more to offer than bitcoin but its rank didn't ever move to 1st . That can also happen to Shiba Inu and doge coin. No matter how hard Shiba will try to kill doge, it cannot do it successfully.