If it was that certain we'd all be trillionaires. What reason is there for alts to rise? What wonderful things have they achieved in the last few weeks?
I think the common assumption is that money will flow out of bitcoin after the fork and in to alts, this will definitely push up the price of alts relative to bitcoin if it happens. It does not mean they will increase in $ value because btc price could be crashing at the time. Of course if anything was certain in crypto we would all be trillionaires but nothing is. If you read the article you would have been able to see that written for yourself.
