I think that being aware of time travel has made many of us aware of timeline changes even if Titor was a hoax. Some of us have had strange experiences and even though I think that Titor was debunked, I am still convinced that time travel EXISTS. If time travel was invented in 3000 years and they come back to visit, then it exists. Actually, having the ability to travel time, IMHO, makes it exist EVERYWHERE at ALL times.
Another point. Kaku says that a type 0 civilization cannot time travel. Then, how can a scientist in a type 0 civilization even COMPREHEND future time travel technology of a type 3 civilization? He can't. The technology they use is probably so far advanced that we can't even begin to understand it. It's like asking someone who took a first aid class to judge brain surgery.
Another point. Kaku says that a type 0 civilization cannot time travel. Then, how can a scientist in a type 0 civilization even COMPREHEND future time travel technology of a type 3 civilization? He can't. The technology they use is probably so far advanced that we can't even begin to understand it. It's like asking someone who took a first aid class to judge brain surgery.