Would you continue to date someone who was not "marriage material" (to you)?

[DRR]

It's simple to me. If dating is a means to an end (marriage) then no, I wouldn't waste my time.

However if you see dating as something you do until you get married, and you can enjoy being in the moment and you can enjoy dating, then sure, do that.

I will also say, who's to say you won't change your mind about someone? It's good to have a clear view of what you want, but don't assume that can't/won't change.