Hmmm, I see innovation. Perhaps failed innovation, but still a new idea.
The spark plug sits in the most valuable volume of the engine. It's right in the top middle of the combustion chamber. Exactly where both the intake and exhaust are the most restrictive. You could let the engine breathe much, much better if only the spark could magically appear in the combustion chamber, without a huge volume needed for the plug, retaining threads and tool access.
One approach is to put the threads and tool access far above, with a long and relatively thin extension to carry the spark into the cylinder.
There is only the minor problems with sealing, corrosion, electrical insulation, thermal insulation/conduction, and dealing with combustion chamber pressure.