That is not limited to Toho, my friend. Trying to make sense of continuity of series films of Universal, Hammer, and the Bond franchise, can be a headache -- the Godzilla films of the 1990s suffered immeasurably from a strict continuity, because when Americans see the films out of context, they don't make sense ("Who's the psychic girl with the goofy ears?," "Why is Godzilla glowing red?," etc.). I saw one of these with an audience who hadn't seen any of the 1990s films before, and they were lost. The loose continuity is much better, because all you need to know is that Godzilla is a big, bad monster and is going to stomp everything in his path, it's not required to see the four previous films to understand what's going on.