A thriving tourist industry depends on having a destination that is safe to travel to. IF Gaza had put its energy towards making Gaza a safe and welcoming tourist destination for Israelis as well as others THEN it might have a thriving tourist industry. You have seen the beaches, yes?
BUT Gaza chose instead to be violent and extremist. A tourist industry can not operate under those circumstances. And, of course, this led to the control that Israel exerts over Gaza.
Egypt had tourist destinations in the Sinai where Israelis travelled all the time, in fact, so much so that the staff would say that Hebrew was the only language they ever heard. (That changed in 2011, however, as Egypt became less safe for Israelis to travel to).
There is no reason why Gaza can't develop friendly relations with Israel. But it has to start with an end to hostilities.