I'm by no means an engineer, but one of the potential issues I see is cartridge overall length. How do you design a bullet with that kind of point and still keep the overall length of the 22 LR the same? Remember, the 22 LR is over one hundred years old and there has to be a million guns out there designed to shoot a given length of 22 LR cartridge. A 22 LR that is even very slightly longer won't feed in some actions or load in some 22 LR magazines, as it is. My Mark II Savage bolt action, for instance, refuses to feed some makes of 22 LR out of the magazine, properly, simply because of a tiny difference in cartridge length from one brand to the next. Autoloader 22s can even be fussier in this regard. From a design point of view, it's probably easier just to start with a whole new cartridge rather than come up with a radical design on an old cartridge that will fit existing guns.
CCI Stingers are a good example of an attempt to maintain overall cartridge length to avoid this issue. To keep that length the same, but actually get the increase in velocity that you get with a smaller and shorter bullet, the Stinger has to use a case that is a tiny bit longer than an ordinary 22 LR case. This still causes headaches in certain models of gun, even though the overall length has been maintained.
I don't think tube magazines would be the real issue as the pointy bullet wouldn't be resting on the primer of a rimfire. Even centerfires do o.k. in a tubular magazine with soft polymer tips like the Hornady Flex-Tip as loaded in the LeverEvolution ammo. Most likely the overall length thing as mentioned above. I haven't had a .22 magnum for years, so haven't bought any .22 magnum ammo recently, but don't they have pointed bullets now in loads like the Remington and Hornady plastic tip .22 WMR. loads ? Seems like the manufacturers could load a semi- pointed bullet in .22 lr. by just seating the bullet a little deeper to keep O.A.L. the same, and still have enough room for the powder charge.