Don't worry. I've heard this type of rumor over the years quite a lot, and each time they spread, it always turns out to be wrong, so don't worry. I know I wouldn't be, since I've been around since before SpongeBob SquarePants aired on Nick, and so far I have seen no signs of the end. Discard the rumors and all will be well.
Spongebob 2 should be based on Battle for Bikinibottom not a day at the beach because it should have more of are favorite sponge in action! it should have something to do with abrassive spongebob since super brawl 3 he should be a huge part of the franchise