In my humble opinion (as a newby here), it's more the case that the SC / ASP (call it either, it's the same engine) engines are sport engines - whether you put them in a plane or a boat. There are still quite a large number of people flying I/C powered planes for sport and aerobatic use (aerobatics obviously requires plenty of torque), whereas I would say that the balance in boats for sport use is much more biased towards electric. So the market dictates supply. There is still some call for marine sport engines though, so they make marine versions as well. Having said that, the performance of the SCs and ASPs can cause some surprises if set up right - but that's a different discussion....
Racing engines for aero use develop much the same RPM (size for size) as racing engines for boats or cars. They are just not very common. OPS and Rossi are good examples of aero racing engines which were converted for marine use. Even though these are old designs, the acheivable RPM is in the same ballpark as current marine racing engines. Metallurgy etc has progressed considerably in the las thirty years, however, so a CMB .45 stands a better chance of finishing a race when running at a sustained 25 - 30K RPM than the older .40 or .45s would.
More modern examples of aero racing engines would be Nelson and Cyclon - primarily for Pylon Racing. These are even more of a niche product than marine racing engines though. As an aside, Novarossi still produce the RX21 in an aero version - again much the same as the car and boat versions. Ducted fan engines for aero use are also often high RPM types (eg OS VR-DF and VX-DF, Rossi, Picco etc).