No, it won't. Maybe in 4-5 years. This is Apple, they make agonizingly slow changes, and when they do they stick with them for years at a time.So you are saying they will always keep 16gb? Really they dropped 8gb in favour of 16gb so change will come soon.
From this point of view, Apple is actually right and doing the best thing for the benefit of itself. Anyway as long as 16gb and 64gb still sell, no reason for them to replace it for our benefit.The 16GB models are like BMW's 320i models. A somewhat gimped lower cost entry for advertising an affordable price point. It exists to get customers in the door to look and then sales people can upsell to the next storage/engine level.
I know logic dictates that RAM is cheap and Apple would do consumers a great service with 32GB as standard since the wholesale cost difference between 16 and 32 is a couple bucks. But Apple isn't a Benevolent Society. It's a for-profit enterprise that seeks to generate as much revenue as market conditions allow.
16GB isn't going anywhere unless iPad sales materially plummet because consumers perceive the 64GB model is too expensive and 16GB a poor value.