When will you hit a point where you can't get both smaller and bigger? Take a MicroSD card, smaller than my thumb and already at 16GB. Flash development is going to get more in a smaller space.
You don't get what flash memory is and how it works. It's an EEPROM memory chip. Basically, it's a bunch of transistors put inside a grid of conductors. you can make the transistors smaller, depending on the technology, but you can't make the conductors thinner. If you make them too thin, they won't carry enough current to do their job. So the conductors have to stay the same size and have to have the same amount of current. Let's assume that there's no limit to how small a transistor you can make ... the conductors still have to stay the same size, and as the transistors get smaller, the conductors will get closer and closer to each other. Since these conductors are inside a chip and are unshielded, ultimately, they will get close enough that one conductor's current will induce a current into the neighboring conductor because of the magnetic field that its current generate. That's when you hit the limit. The only way to increase capacity for flash media from there is to increase in size.
Besides, as mentioned previously, it doesn't move. Shocks and bumps are irrelevant, there's nothing to get out of alignment, which is very important for laptops and still very nice on desktops.
You're thinking of optical media in terms of CDs, DVDs, BluRay, etc.
Optical media does not have to be that way. The technology was developed this way because of the way hard drives have worked in the past. Same thing with floppy disks. To have a spinning disk go around and read data off of it as it goes past is an idea pretty much taken from vinyl record players. Very outdated.
But it doesn't have to go that way. You can have your sensor and writer travel about your media instead of having the media moving on you.
The problem with shocks and bumps is that current optical media drives are poorly constructed and designed. They have a spinning disk ... which wobbles as it spins which as quite bendable and is very badly anchored at its center. If optical media drives were designed to have s solid build and the optical media was anchored at several points on the outside as well, that wouldn't be a problem.
If you have the media sit still and have a sensor inside the drive that reads it which can quickly move across the media, you'll have very fast speed and very little moving parts, maybe even no moving parts whatsoever.
So, you'll ask, why hasn't anyone thought of this yet? Well, they have. Then you'll ask why the technology has not been put it practice. And the answer is: it's too expensive to develop, it's much easier to develop anti-skip technology on an already-existing invention than pour a whole bunch of money to pretty much reinvent the wheel. And even if the technology was commercialized, it would cost much more to build than your typical optical drive, thus its price would be astronomical.
And you realize that there will be a tipping point for optical as well? Space is finite, you're going to run out at some point, it doesn't matter what format you're using. I'll take the one that doesn't have moving parts, thanks.
Again, you don't know how optical media works. It is based on having a track of data on a reflective surface and shining a laser down to the surface. Based on whether the light is reflected off of that small point on it, the receiver detects a 0 or a 1. This track is like a spiral on current optical media ... but it can be put in rows, grids, whatever shape you choose to have it as. The way they fit more data on the same size optical media or a smaller optical media is they make the reflective points on it (the spots which tell whether there's a 0 or a 1) smaller and smaller. And in order to detect these points, the laser that shines on them is made of a smaller and smaller wavelength. Thus ... there is almost no limit to how small you can make the little dots that store data ... and they can go way smaller than a transistor or a metal conductor inside a flash memory could go ... and there's almost no limit to how small you can make the wavelength on a laser go ... again, you can make it much smaller than the smallest thread of metal you can make.
But, you may be right. There is a limit to how small you can make the data on optical media. It's called the atomic scale. You can make the wavelength of light however small you want, but you can't make an atom smaller than it already is. And if you want your light to bounce off something, it has to have matter in its path. If the wavelength is too small, it passes in between the atoms and does not reflect.