Bitcoin does not scale efficiently on it's own. This is correct, and some developers have even stated this or something of similar meaning. This does not mean that we should not scale Bitcoin. This does not mean that we should only scale Bitcoin via block size increase either. You'd have to look into block propagation times and orphan rates to get a better insight. There were good presentations in the recent workshop. What Bitcoin needs is a dynamic block size in a combination with the Lightning Network, sidechains, etc. Only then will Bitcoin be able to be used by the majority.
Please move beyond the simplistic 'every-coffee-and-bagel-on-the-Blockchain' paradigm. That POV is so three-years-ago, and was rubbished once and for all by a single domination post.
I concur. This is pretty much impossible due to the two things listed above (propagation times and orphans); impossible without the Lightning Network or something else.