"The encouraging thing today is that we're kind of converging on good practices in language design." - doubtful that we'll arrive at good practices in language design through incremental steps from a flawed base. All the mentioned languages are low-level.
"Therefore... what? Just give up? Or start over from a non-flawed base?" - those would both be ways to avoid the presumed local optima, yes.
"Which is what? Still to be created, or does it exist?" - several different 'initial stakes'/bases in the space of programming languages exist/were made/can be created than the family of languages mentioned in OP. Exploration from those might yield better optima. The widespread adoption of the current industry 'standard' languages seems an accident of history, not guided by quality of language.
"Are the bases flawed because they are low level?" - yes. A significant part of the computing field is about abstractions. Improving the level of the technology is one of the arguments the article here makes too. Besides, it's the implicit admission of everyone who doesn't advocate/write assembly.
