This is reported by travel website Turisti.is who add that British travel agency Discover the World are predicting the same thing. 
Studiosus has been booking tourists to Iceland since the 1970’s. 
“We won’t be taking Iceland out from our destinations but we will be cutting down our trips because we don’t expect that many will be purchasing them,” says Manfred Schreiber at Stuidosus. noncleared-maintext”>
Representatives of German travel agency Studiosus, who offer trips to Iceland, expect that the high prices will deter people from booking trips next year. British travel agency Discover the World says that for the same price as an 8 day hiking trip in East Iceland they can offer a two week trip around New Zealand.   He also has some harsh words for the Icelandic Government speaking to Túristi.is in April when he said that they seemed to be wanting to kill off tourism with increased taxes.