Memory capacity was being used lately as a method to differentiate between models, so a cheaper one usually includes less memory or there are two options, for instance 16GB or 32GB when the memory is not very expensive nowadays at this degree. It's not really smart (well, it's called smartphone) to have the possibility of using an external memory with considerable speed, up to 10 megabytes per second in class 10 Secure Digital cards, and do not let the operating system use that memory for installing applications as a native option. The marketing schemes could say it, but finally the user experiences problems as some applications do not allow this option or other complications arise as the application developers have freedom to choose and with it, also the possibility of blocking some users.
So a 20 Mb application only needs two seconds for being loaded into RAM for faster access so this cannot seem at all time that a user can't stand instead of throwing the electronic device away because at the end, multiple users have now issues to install applications since the internal memory is full and even updates cannot be downloaded. Even with some tricks that the public might not know or apply in a big percentage, common solutions are buying another model or uninstalling applications for freeing space.
One of this is, as you may guess, a source of income to several companies and at the same time, another for electronic waste and a true movement of irresponsibility toward the public environment that includes the air to breathe, water to drink and for watering the aliments. So for this reason everyone is green during its life and it should act accordingly, with intelligence and not the opposite.
It's strange that nobody in the development team of Android did not predict that this case of low memory could create to numerous users the sensation of that they need a new device, providing solutions at an easy access, for every level of expertise in the OS for instance in the menu.
Sometimes the solution is to gain extra privileges using the root method (and some say the device loses the warranty so it's a risk) or perhaps this one.
Even this way, this reality that everyone can see and judge should disappear quickly, at the same fashion of mendacious words or with half-truths from everywhere.