Nobody HAS TO buy shares. It's more likely that some may need to sell shares, if anything.
What's a company worth? Assume a P/E of 20, which is greater than the S&P average.
With around 800,000 shares each 1 million in earnings results in a share price of:
1 million earned x 20 $/share / 800000 shares = $25/share
So each million in annual earnings adds $25 to the share price.
Last quarter they earnbed around $250,000. If they maintain that for the next three quarters the company will be worth $20 million or $25 per share.
If they earn $2 million, then $50 a share. $4 million, $100 a share.