Yes, I think that the popularity of cheap smartphones and tablets with 16GB or less storage space is keeping mobile game makers from releasing longer games with better graphics, more realistic sound, more levels, side quests, and mini-games built-into the game. Game makers don't want to prevent gamers with phones with less storage like 16GB of space from playing their games.
I feel once most affordable smartphones and tablets have 64 GB or more internal storage space, there would be more longer mobile games with better graphics, more realistic sound, more levels, sidequests, and mini games because of the large amount of storage to store larger games on a phone.
Maybe, though even 16 GB would be useable for better games if game makers tried to compress the resources probably. I mean, your average SNES or GBA era game was in the couple of MB range, and looked about as good as most of the more 'casual' titles on phones today. Even the fancier 3D titles could probably fit better if they didn't leave the graphics/music at too high a quality level.
I feel a lot of mobile gamers with nicer phones like an iPhone 6S, and Samsung Galaxy S6 would want the best looking graphics, and realist sound, and don't want compressed video, and audio which may make their gaming experience not as enjoyable. Having more storage space could make open world games like Gangster Vegas have bigger levels/maps with higher quality video effects.
It maybe tougher today to sell a game with average storylines, and basic graphics like from the SNES or GBA compared to making a game with an average storyline with great looking video, and realistic sound.
