For me it was all quite simple. I wanted to ride long distances. I started out with a lower priced bike. It was okay but it felt heavy. I didn't like it much but I tolerated it because it got me from point A to point B, and I did get pleasure from the riding. It still rode a lot better than my 1970s department store 10 speed. But not at all as good as my 1980s fat tube Cannondale.
Then I asked a friend what he thought was a better bike for my goal of long distance cycling. He suggested a specific brand and model. I rode a similar model at a local bike shop and instantly noticed the ride was much better than my old bike offered and the lighter weight was a real blessing. I was sold. I put down my money and ordered the better bike. That is the one I'm using today.
Eventually, I will want to move up to an even better bike -- a real touring bike. I expect it will cost me a bundle, but since I'm starting to see real health improvements for myself, and I'm driving my car so little even now, I'm fine about the cost. By that time, I'll have more riding experience, too.
So I think you'll need to understand that a bicycle is not a one-time purchase any more than a car is. I've had a few cars by now, and I've had a few bicycles. You too will have a few bicycles. You buy a bike, no doubt the one that is correct for your budget, and ride it for a while. Then you move on to the next bike. There will be a natural progression of I-want-a-better-bike if you keep on riding. It is normal and happens to all riders. I wouldn't ride the "10 speed" I had in 1975 today when there are much better quality bikes out there.
Bob