1. That isn't a problem since you need only use sealed bearings like you do in most of a bicycle's bearings.
Adding seals would increase drag and eliminate the friction advantage that's their major claim for this system, which makes the whole exercise largely pointless. They expressly stated that their main purpose in designing it was to create the lowest friction drivetrain possible. While they succeeded in doing so with a design that works fine in a lab, it's not practical in the real world.
2. That does appear to be a problem without a solution. Though perhaps a carbon fiber flat plate backing would be effective.
Good luck with that. The way the system is currently designed, there simply isn't any room for a rigid enough structure, regardless of what it's made of.
3. Those finger if made properly would not flex. They are not "tiny".
Did you actually look closely at it? The ARE tiny and they're aluminum, which means they're also weak and prone to wear, especially when they get dirty.
4. Shifting is really easy and I'm sure they have that figured out. You run a shift cable or shaft through the center of the drive shaft and using slots in the drive shaft pull the drive bearing fore or aft.
If it was that easy, they'd be doing it already rather that trotting out a single-speed. Right now, even if they do have a way to shift it, it simply will not work under any significant load, which is very obvious.
There is a lot of troubles with the present day chain and sprocket and multi-derailleur system and everyone is investigating ways to get away from them.
Who exactly is everyone? I don't see a huge clamor in the market for alternatives to systems that currently work quite well. Current shifting systems aren't perfect, but they're very efficient, reasonably priced and easy to maintain.
The CeramicSpeed system is at least a try at a change away from dirty broken chains that wear out rapidly and cassettes that wear out and the entirely open drive train that attracts mud and grease from miles in every direction.
Kudos to them for thinking outside the box, but they don't really have a viable alternative drivetrain here.
How exactly does a drivetrain attract
grease? it's not as if there are puddles of it laying around. For that matter, how does it
attract anything?
With PROPER lubrication, chain drives can stay quite clean and they last for thousands of miles before anything needs replacing.
There is actually an internal 10 speed hub if memory serves. The problem presently is that whether it is strong enough to withstand the huge pressures on it.
There have been 14-speed internal hubs on the market for over a decade (Rohloff), as well as numerous others with fewer gears from a variety of manufacturers. The problem with internal hubs has nothing to do with pressures and in-fact, they hold up even to off-road use. The problem is that they're heavy, expensive and are less efficient than chain drive systems.
My take is that we could probably make a very simple hydraulic drive system totally enclosed within the bottom bracket and rear hub. I'll have to think about that.
There are already BB-based drive systems and they suffer from the same problems as internal hubs. weight, cost and efficiency. On top of that, the frame has to be constructed specifically for a given drive system, as they all unique and there are no standards for them currently.