The cage is an integral piece of the UFC brand. There is ZERO chance they ever get rid of it. Not unless the company itself fails and reorganizes under a new name or something.
As far as the cage itself, there are pros and cons just like anything else in life. I hate stalling and cage fucking just as much as anyone, so Im not advocating for that type of "entertainment", but the cage does create certain dynamics that would never develop in a ring.
In a ring a fighter can retreat to the ropes in order to reset. Floyd was a master at this, as he never STAYED on the ropes, but would give ground to his opponent if they were being overly aggressive and then pivot off of the ropes and end up right back in the middle of the canvas, once again in control. This is called ring generalship, and there is none of that in the octagon. Yeah, fighters can get on their bike in the cage, but there is really nowhere to go. Every time someone tries that back-off retreat into an escape they end up giving up their back.
The cage passively forces guys to kind of draw a line in the sand and bang. The only way to avoid that is grappling and wrestling. Which brings me to my final point, a ring will fuck wrestlers and grapplers and strikers will inevitably begin to have an advantage and every champion will be a striker. Wrestling shoes will somewhat help negate that, but overall its just too much to mitigate through accessories and planning.