Apple's storage pricing model would be unsustainable in a competitive environment. Entry level products with 16GB exist solely to establish a 'free' subsidized level while practical use requires a US$750 64GB model.
Ordinarily Samsung and Moto would make a phone of similar quality and charge the market rate of $8 for the 64GB upgrade to undercut Apple.
Unfortunately it's not a competitive market. Apple's 2013 iPhone 5S still has lower power use and more processing power the current Samsung phones because Apple invested in chip design and shipped an AArch64 chip Samsung can't match even with two years (1.33 Moore's Law cycles) of process upgrades and access to Apple's tapeouts.
Apple's screen process is still brighter with more faithful colors. Apple's case design is still more fashionable (even though I don't like the latest ones, they look slick). Apple's net software and services like maps and backup are catching up to Google and ahead of M'soft or anyone else. Apple still has better control over power consumption and background processing in its OS. Apple's user experience is still clearly better and easier than Samsung or Google.
A lot of that is Google losing interest in Motorola, the Nexus brand, and Android. The Nexus 5 was the last inexpensive high quality pure Android effort and it wasn't profitable. Motorola wasn't worth keeping. Android is good enough to keep Apple and Microsoft from squeezing Google off the net and that's all Google needs. Google hasn't even updated Android to take advantage of AArch64 which cripples all the Android phone makers against Apple.
Ultimately, Google knows that they can't compete against Apple because carriers have contempt for quality. No other maker but Apple has loyal and lucrative customers that will switch carriers to keep using Apple devices. Thus no other manufacturer has leverage to get the best quality devices it can make to users. Carriers want your phone crippled because they dream of controlling you and governments hand them monopolies so they can control your device maker.
The result is that only Apple can make a top flight device. And therefore they can use monopoly price discrimination tactics to bleed extra money from you for 64GB.
It beats the alternative which is carriers ruining all devices including Apple. I like Apple robbing me a lot more than AT&T or Telcel or Softbank or NT&T or China Mobile or Verizon.
