The "models are getting better with every breath you take" is just an unproven claim that the AI companies want everyone to believe and want the evangelists to use in every argument.

The AI companies have to put out new models regularly, not because of any improvement but because the failure to do so will signal stagnation. That's how it works in the tech industry. It's not like the wine or cheese industry where you just follow your hundreds-of-years-old recipe exactly and people buy the product because of that.