Switzerland spends half as much as Sweden on its annual military spending as percentage of GDP (also less in absolute terms), and they can credibly stay out of NATO, so why couldn't Sweden? Geographics? I don't buy it.
Also, if Sweden wanted to join tomorrow morning, they would have the application granted after lunch the same day. NATO has been salivating at the thought for decades now, and considering Sweden's military is already running on NATO standards, its officers take all the NATO courses, and the military partakes in all major NATO war games, it's not ridiculous to say that for all intents and purposes, Sweden is basically already a member, just not officially.
The pro-NATO side's argument tends to be that since Sweden's already basically a member, at least it should have voting rights by the merit of being an official member. That's their top argument IMO.
Joining NATO would be a massive provocation towards Russia that I don't think neither Sweden nor the surrounding nation states would benefit from. I'd rather not choose sides in a Second Cold War, since either side in such a conflict would be rather contemptible. Now, it's pretty clear "we" already did, however.