It generally always comes down to what works within one's budget and obviously their playing characteristics based on where they play most often.
The greens where I play are notorious for being soft... I could certainly justify playing a lesser-expensive ball that doesn't "bite" off of short-iron approaches because the proximity-to-the-hole is somewhat mitigated because of the receptiveness to the greens.
So essentially it comes down to (1) how straight can I hit the ball, (2) how much further the ball travels, (3) how the ball reacts from green-side chips and pitch shots and (4) how soft the ball reacts off the face of the putter. And it's worth nothing that not everyone needs all of those boxes ticked, at least based on whether one is paying $2.50 for the ball versus $4.00... it ultimately comes down to how the ball one chooses performs based on their individual expectations.
I've spent the past month or so playing the ChromeSoft from Callaway. The ball feels great off the club, whether it's an iron, hybrid or driver. It's soft... it feels like it stays on the face of the club just a tad longer, which is great as far as being able to feel like I have some means of control as far as accuracy. Is it a better performer than my more-economical choice 3-piece Srizon Z-star? Not really... there's not enough of a difference in green-side performance to justify another 7-8 bucks for what I essentially feel is a very comparable option to the ChromeSoft. Again, I'm not playing most of my rounds on hard, firm greens where there might be a premium on backspin off of short or mid-iron approaches. And as far as approaches beyond mid-iron approach shots - I'm not expecting much in the way of hit-and-hold type shots with hybrids and fairway woods. So it's all relative, too.
But for several seasons now I've played more than enough rounds with the uber-expensive ProV1X to appreciate the overall performance characteristics compared to the lesser-expensive options... part of that has to do with the way I compress a golf ball at impact, the understanding that no matter which ball I play - I'm generally hitting the ball fairly straight with a somewhat repeatable angle-of-approach, and ultimately the green-side control in addition to the added 8-10 yards off the tee ultimately makes it my ball of choice in a competition round.
I guess you could settle the debate one simple way. If you're a competitive golfer who plays in a dozen or so tournaments each season - which ball do you feel most confident playing? If you don't compete in tournaments and you prefer to compromise via the cost-vs-performance ratios - it really just comes down to personal choice. But if you are a tournament player - you spend X number of dollars per season to compete in those tournaments, and you probably don't mind spending an additional $7 or whatever in those instances to play the ball that you feel gives you the absolute best performance.
And if you're accustomed to playing NXT's, Srizon Q-stars or Z-stars, the low-compression Wilson offerings, or even the TopFlight Gamer - it essentially comes down to your game, what you expect, what you're willing to part with as far as cost, and being content with results. So I can't argue the the ProV1X is the best overall ball on the market for everyone, but for me - it most certainly is.
Lots of really good balls out there, especially compared to those that were manufactured just 10-15 years ago. You can compare the most economical ball today versus the ultra high-end performer 15 years ago and the current economical ball would probably out-perform the high-end ball from back in that era.
There really is no one-size-fits all approach to golf ball choice. It just primarily comes down to budget, reliability, performance and how those things mesh with one's own expectations.