It's surely both.

Look at the newest questions: https://stackoverflow.com/questions?tab=Newest

Most questions have negative karma.

Even if somehow that is "deserved", that's not a healthy ecosystem.

All that is left of SI are clueless questioners and bitter, jaded responders.

SO worked when "everyone" was new to it, and they felt energized to ask questions ( even "basic" questions, because they hadn't been asked before ), and felt energized to answer them.

SO solved a real problem - knowledge being locked into forum posts with no follow-up, or behind paywalls.