The amount of misinformation/speculation without any knowledge here (and on Reddit) is staggering.
Short-selling is a misunderstood concept, not easy to grasp for sure. But let me tell you some of the basics:
A short sale is when someone borrows (person B) a share from a shareholder (person A), then sells it to person C. Every short that is sold, creates a "synthetic" long position that gets added to the float, in terms of tradeable positions.
So let's say a company has 100 shares outstanding of which 50 are held by management/large holders who don't trade on a daily basis. The remaining 50 would be the float. If there would be 50 shorts (100% short interest of the float), then there would be an additional 50 synthetic longs traded in the market. So the "real2 short interest as a % of float would be 50% (50 shares shorted vs. 50 float + 50 synthetic longs). A share can be shorted many times, i.e. person C which owns the synthetic long, can in turn lend their stock out to person D that can short it and sell it to person E.
There is no time-limit on shorts (unlike options), but the longer one holds, the more expensive it gets (because cost to borrow a stock like GME can cost 50% on an annual basis, so 0.1% per day).
Short squeezes can and do happen (evidently) and it happens when (i) the position gets too big in the hedge fund portfolio and they sell voluntarily or (ii) if they have bought it on margin with a prime broker and they don't have margin any more, then one can force liquidation.
However, important reminder here, the shares that are sold short are not static. I am pretty sure the "old" or initial cohorts of the GME shorts have all covered, but they have most likely been replaced by new ones and they most likely have much smaller positions (per fund) than the initial short cohorts, because they see the volatility of the stock. The new shorts can afford it to go up much more than the initial ones. It is much tougher for it to be a 10x from here now that the market cap is so big (would need significant money in-flow to continue), compared to the past.
And when these funds cover, wouldn't surprise me if new ones come in and just take over the borrow. Because ultimately this is a game of how long this can go on and the hedge funds believe that this stock is not worth more than $10-$20, so it is a safe bet that they will eventually be right if they can "stomach the volatility". So even if there is a further squeeze, new ones will likely come in and replace them.
Then the big question is - what is the end-game here? Say that Reddit can force a short squeeze at the end of the day, when the shorts are gone - there are not going to be enough incremental buyers (except retail investors that can perpetuate the bubble) and then the bubble will most likely deflate. Short squeezes have happened in the past with Volkswagen being the most famous one, and there is a spike, but then eventually once the squeeze is over, the price will return to levels more appropriate. Because if the short squeeze is over, then what are people buying it for?