Facebook Messenger, for instance, is just "Messenger", removing the company name. There's a built-in app named that as well, and I always forget which is which.
Unfortunately, not a solution for iPhones.
I have an old but trusty iPhone 4S with 16gb, so I certainly have memory problems. however, I've found that programs usually aren't that big – it's usually the data. Photos, podcasts, caches... those are the things that really add up without you noticing.
A lot of apps can be several GB by themselves alone, e.g. some 4-6 GB game titles, etc. Music apps with sample content tend to be on the multi-GB camp too.
And of course the user might also have most of those 64GB taken by his music, videos, and photos.
A bargain at 16 gb upgrade for $100 from Apple /s