WTF are you talking about? When did we go from 1/8 scale cars to full-on race bikes and sleds? RC 4 strokes need no oil injection. Move to DI and you now NEED Oil injection as the fuel/lube mix isn't moving through the engine, IN AN RC APPLICATION.

And I'm sorry, simple Hot rodding can almost double the output of a 4 stroke motorcycle engine. Jets, Exhaust, timing curve and camshafts. In that order.

The big difference IN AN RC APPLICATION between 2 and 4 stroke are thus:
2 stroke needs 20K+RPM to produce peak power, some to 40,000.
4 strokes produce at about 1/2 that RPM.

1/2 the RPM means 1/2 the fuel used for the same displacement at a given power level.

4 strokes are easier to tune
2 strokes are lighter

2 strokes have "toggle switch power" On or off.
4 strokes have a more linear torque curve, meaning applying that power should in theory be easier.

2 strokes need smaller gearing to use the 20K+ RPM where the power is.
4 strokes could use 1/2 that gearing(higher) to achieve the same power to the ground.

Remember we are talking GLOW RC ENGINES. Not spark ignition engines. Remember these are all 2 and 4 stroke DIESELS, not spark ignitions. Enough residual heat must be retained in the glowplug to ignite the fuel mixture. Kinda hard to do with an injector squirting fuel in just before TDC, cooling the piston and head.

2 stroke model engines dominate because of 3 factors.
Ease of production
Simple design
excellent power to weight ratio.

4 strokes always have been a novelty in the RC world, much like radials, Wankels, twins, triples, quads and pents.