The only coin that is somewhat "proving" that a higher blockchain capacity is possible is Ethereum because of their high transaction load in the past months, but the differences with Bitcoin are not very high.
Hasn't Ethereum actually showed that they too have scaling issues? Or are you talking purely blocksize?
yeah. they're not exactly knocking out of the park. exchanges had to shut down ethereum movements because of overload. bitcoin's never had that problem and never will.