It might not be what the inventor imagined, but this is hardly an unexpected outcome. BTC in particular was doomed to either be a forgotten novelty, or the wild speculation instrument we see today. It doesn't really have a good mix of features for a usable currency, and its appeal as a currency is largely limited to those ideologically pre-disposed to value anti-inflation over other limitations.

The limited throughput of the blockchain was always going to be a particularly bad problem.