The article quotes Perls saying (in 1969) "As Albert Einstein said to me". That's not evidence of Einstein saying anything, but of Perls appealing to authority.
When Perls published the quip in the 1940s he said "a famous astronomer", not Einstein. He wouldn't have put it that way if Einstein had been the source, especially since he mentions Einstein elsewhere in the same paragraph.
The Quote Investigator is extremely conservative in refuting bogus quotes; when they say "probably not", they mean "hell freezes over if". The readiest explanation is that Perls, a showman who (unlike Einstein) often made caustic quips like this one, simply optimized his story over time.
http://quoteinvestigator.com/2010/05/04/universe-einstein/