May I ask... What do you do on your devices that you need that much of onboard memory?
My iPhone is still 16Gb. I agree that it's little too tight amount of storage, but easily manageable with cloud storage.
My iPad is 64Gb and I have used approximately 40% of the space so I still have loads of storage left.
My Mac, yes a Mac which I use to do serious stuff with has 256Gb of storage and I think I will never get even close to filling it completely.
From my personal point of view it's basically impossible to fill 256Gb or even 128Gb device. How do you do this? Seriously? It's 2015. We have cloud services and streaming services. You can download your favorite songs and movies locally and stream everything else. Having your whole library locally isn't an excuse. Thats just waste of space.
It really annoys me when people post such things assuming that every one has access to an internet connection 100% of the time. I've got news for you this is not the case. There is no way you can rely on cloud services and streaming 100% of the time. It's impossible. I live in London which by all intense and purposes is one of the largest cities in the world but even here I do not have access to a decent and/or unlimited data connection all the time.
My cellular plan is limited to 8GB per month and there is no way to get wi-fi at least useable wi-fi for cloud service and streaming whilst on the go walking or in the car. When travelling on the subway underground there is no connection at all except at certain stations but not in the tunnels at all. There is no way I could rely on a data connection 100% of the time.
My mood changes all the time and I like to listen to different music and podcasts or watch movies or TV programs on my phone or iPad. For this I need a large storage capacity. I shouldn't have to nor do I want to manage my storage mainly because I may end up not having what i want to listen to or watch on my device. I have a 128GB iPhone and iPad and I have around 20-30GB free on both. I could easily fill all of it up and even make use of a 256GB storage option.