Actually, you kind of answered this in your first post, but sort of handwaved it away, when you referred to issuing more stock. This is not such a rare event, and can be quite crucial for a company seeking additional capital to grow its business faster or to pay off existing debt coming due.
Also, stock can be used as currency for buying other companies. To give a simplified example, if company A with 80 million shares outstanding and a stock price of 100 wants to buy company B at a negotiated buyout value of $2 billion, they could do so by issuing 20 million shares to the stockholders of company B.
At the end of the transaction, the stockholders of company A would own 80% of the combined company and the former stockholders of company B would own 20%.
If company A’s stock price had only been 50 but everything else was the same, they would need to issue 40 million shares to the stockholders of company B.
In this case, the stockholders of company A would own 66.67% of the combined company and the former stockholders of company B would own 33%.
Obviously, the shareholders of company A would be happier in the first case, made possible by the higher stock price.