The two have nothing in common. Infatuation is "crushing" or "pining" for somebody you don't really know. It's wishful thinking or projection.
You can be infatuated with a stranger, a song, shoes you never wore or a car you've never driven.

You can't have romantic love with a stranger. If you love someone or something you'd take good care of it and protect it even if you know you'd lose it.

The key thing about infatuation is the lack of knowledge of the desired person or object.

Infatuation is selfish and romantic love is selfless.

Thier almost antonyms.

Infatuation shrinks over time. Romantic loves grows over time.

I think one is a quick, spontaneous reaction, imagining the possibilities, while the other is a deeper, richer, more solid realization that the other is not perfect, but that doesn't matter, it is overridden by the overall grip they have on your soul, your mind and youir body. An analogy : most of us pick up books, based on the cover, the blurbs, the first few pages, and maybe the price (!) If it is a good book, you can't put it down, it's a page turner, and you might go back and reread it to pick up what you missed the first time.

At the age of 57 I can announce that I have no idea. Sorry I'm not much help.

This is complicated. Long lasting love can happen between two people who cannot live together. I have had this happen to me. Found the love of my life or so I thought, lived together for four years. Really thought we were perfect together, but then came the end. I would still say we are friends although it has been 35 years since I last saw her. About 35 years ago I met another woman, a friend of a friend. Over several years she would come over to the place I shared with several other men. I found myself being followed during a get together of about 25 friends, found she had broken up with her boyfriend. I got her number and called her. I figured it would be a one date deal as we were in two totally different places financially. No pressure on the first date, we had fun checking out a movie and having banana splits. Sat and talked the rest of the evening, been married 28 years. There was never a lust stage, don't get me wrong, but I guess since we had known each other for a time we knew we were in the relationship for more. I do not know if this is helping.

Well my opinion is that infatuation is admiring someone to the point of obsession. Romantic love can involve the sexual attraction or more. Depends on what you want from a relationship.

....and who is there to say that infatuation can't last forever?

Nothing wrong with infatuation, it is exciting. Romantic love, to me, always meant that I felt more like I was me while in love with someone than I would otherwise, like something would be missing from my own self if my love wasn't there. It's all subjective, however.

Hormones!

I think infatuation is all the excitement and entertainment that comes with falling for a person. Love is more personal and less glamorous.

I don't know if there is a difference between infatuation and romantic love. One might say that infatuation is what is held in your mind and nothing may come of it. Romantic love might be the next step as you may need to actually have the person in order to be romantic as opposed to it just being inside your head. Or what about lust? Way too many people confuse lust and love. And then how many types of love are there.?
And to what category does lasting love belong to? What about knights and courtly love? My guess is that everyone has a very different idea about what love really is.