In other words you're inventing some silly criteria that I'd guess you'd pass that others wouldn't. What I would say to that is that if you dismiss someone else's experience because they can't do some task you think they should be able to do rather than understanding that their experience probably brings something else to the team then that's your failing, not theirs.
For a little annecdata - I've been a dev for 25 years, with a senior level (and above) title for about 80% of that, and I reckon I'd take at least a couple of months to get to a point where I was happy with golang. I guess that makes me a junior in your opinion. However, instead of being able to get up to speed with a language quickly I bring a fantastic level of respect for users, a talent for technical writing, a belief that documentation is actually important, a sense of fun and joy in making high quality software, and a deep understanding of browser-based software. If I was looking for a new team member I'd seek out someone a bit like myself rather than someone who can learn a new language faster.
For a little annecdata - I've been a dev for 25 years, with a senior level (and above) title for about 80% of that, and I reckon I'd take at least a couple of months to get to a point where I was happy with golang. I guess that makes me a junior in your opinion. However, instead of being able to get up to speed with a language quickly I bring a fantastic level of respect for users, a talent for technical writing, a belief that documentation is actually important, a sense of fun and joy in making high quality software, and a deep understanding of browser-based software. If I was looking for a new team member I'd seek out someone a bit like myself rather than someone who can learn a new language faster.