I understand that you're worried about the development of a "friendly and inviting" user interface and that you're confident that it's only a matter of time for scalability issues to be solved. I would like to suggest the idea that maybe there is reason to be just as confident about the innovation and implementation of "idiot-proofing" solutions for the cryptocurrency user interface as for the resolving of possible scalability issues! Andreas Antonopulos has mentioned that that bitcoin does face "some very significant security problems related to the ownership and control of bitcoin keys[...]for the end user", the implication being that the technology may not be user-friendly enough for mainstream adoption (43:15-43:24, video linked below). He does however go on to say that he DOES BELIEVE that "over time, we are going to see the development of more secure mechanisms" and that "for every problem [he] sees in bitcoin, as an entrepreneur, [he] simultaneously sees a tremendous opportunity" (43:53-43:59, video linked below). There IS a strong business incentive for the innovation of idiot-proofing solutions to cater to the requirements of the mainstream adoption of cryptocurrency. The market introduction of the Trezor hardware wallet is representative of this commercial push towards the simplification of the use of cryptocurrencies. Today, the innovation carries on with products such as Javvy with the "support of the multi-signature authentication" for even more approachable user interface (https://javvy.com/wp-content/uploads/2017/08/javvy_prospectus.pdf). :)