Sorry, but the article made me laugh. 70% of executives claiming to be experts in something just means that the something is now a buzzword.
You probably would find a only few percent of computer programmers, mathematicians or engineers claiming to be experts at blockchain.
Personally, I wouldn't consider myself an expert until I've designed, implemented and optimized several working blockchain solutions. The number of true blockchain experts in this world numbers in the thousands. But, executives would declare themselves experts in the field for just knowing that it has something to do with computers.
you are absolutely right