Hi,
It depends on a lot of variables, but ultimately the question you're asking is that most things are not going to be substantially better, ever, from the budget standpoint speaker. If you consider that even a cheap $25 speaker is able to perform pretty frigg'n good for that $25, how on Earth do you get massive returns on something that is $500? $1000? More? You start to see massive diminishing returns. Everyone will have their argument for a price point as a break point where you have a sharper drop in return for the cost. But really, the decent budget stuff is about as good as it gets for the money and everything is a massive massive diminishing return for cost as you increase cost.
So more variables become part of this to help differentiate it for you. It's not the same for everyone. Your preferences. Your true needs. Your room. Your source content. All this stuff matters and plays a role in this.
Could you upgrade those Jamos? Sure. Would it be way better? Maybe, maybe not. It's hard to define way better. From a metric standpoint, it wouldn't be difficult to beat them. But from a psychoacoutic standpoint, it could be possible to enjoy them better than a $100,000 set of speakers. We really are not that great at hearing and we're fairly bass deaf. Few people have exceptional hearing that allows them to accurately and precisely and consistently pick apart something, without education and experience and still will be beaten by metrics.
Your room matters. Your purpose matters. Your content matters.
The best thing is what you did. You auditioned more speakers. Unless you're into metrics, the best way to find something to spend your money on is to listen to it on well known content to you. If it sounds better, then you're set. There are so many luxury ways to get your hands on so many different speakers for near nothing, you buy, the ship to your door free, you audition, and you send them back if you want, no questions asked, for free or a small fee, to audition most speakers. Use these luxuries. Lots of companies do this. You can try it out yourself. Keep the one that wins over the rest. Do a shoot out.
Instead of focusing on price, start focusing on speaker design and some specific performance metrics. There are excellent speakers that are inexpensive. And there are expensive speakers that have poor performance.
Very best,