Person didn’t move over to the empty seat on a 9 hour international flight even though I kindly suggested it right off the bat

Boarding was almost finished and I was overjoyed at seeing that nobody else had been seated in my middle-of-the-plane row, until this young guy came and sat right next to me. Initially I thought “ok he’s probably just waiting until boarding is finished to move over” but as we started to actually pull away from the airport I said “you know you could probably move over so we can both have some extra space” to which he responded “yeah I probably will, just I think my friend will come sit in the empty seat in a couple hours”. I was like…. Okay??? His friend never came and this guy proceeded to use the extra seat for his stuff, his garbage, even to lay down and one point and have extra space to cross his legs and i silently seethed. I was honestly a little perplexed lol. Curious to hear possible discourse that comes from this post, would you have been mad or was I expecting too much?