Indeed, a lot of people treat meeting a partner as a step on some planned self transformational journey, where they try and manifest "the new me" .. a recipe for misleading the other party.
That's literally the first time I've heard of that. I think that in reality there are not a lot of people who think as you describe, and I believe the most likely explanation for your conclusion is that you're in a bubble.
Same with getting a new job, moving house or having a child. Any "big commitment move" involves long term hopes and intentions that are often fanciful.