Well, that kind of was exactly my point, although I feel now I didn't make it very clearly.
Someone might shoot down a prospective author who intends to write a book featuring a young protagonist getting a formal education in magic because it's "been done", but the resulting works are very different. It was a counterpoint to the article saying that we should not try to realise our ideas because someone somewhere has had "the same idea". They probably have had an idea which could be described in a similar fashion, but it doesn't really mean its the "same idea"
I probably stumbled a bit describing those books as the same concept when I should have put "same idea" in quotes
To stretch the book analogy beyond breaking point, it would be like if Patrick Rothfuss released The Name of the Wind, and JK Rowling immediately put out "Harry Potter and the Kingkiller Chronicles, now with added Kvothe", and basically used her name and the Harry Potter brand to outcompete Rothfuss selling the same thing. (Obviously for books, you've got copyright, but there's no copyright for your favourite app idea.)
I think the extent to which that is actually true is hard to say, but I think it's a different point to the one you're arguing against here.
A wise friend of mine once said, in regard to "ideas are nothing; execution is everything": you can tell a thousand artists to paint a portrait of an Italian woman with a countryside landscape behind her but, good or bad, none of them are the mona lisa.