They're also returning like $6 billion/year to their shareholders via dividends -- if they had just hoarded that cash, their share price would obviously be much higher.

Isn't share price influenced by future dividends? Why would preventing dividends and hoarding cash (reducing expected future earnings of shares) drive up share price?

It’s a bit more complicated than that, it’s also a bit more complicated than what I’m about to say.

Functionally speaking when a company issues a dividend of $x the stock price S will drop to S-x on the ex dividend date. This makes sense as the company now has $x less per share. The shareholder is at a wash as well. They had S before and now they have S-x+x. No value was created, money was simply moved.

Given the above you can more or less value dividends using discounted cash flow. A ~3% dividend is CSCO’s case isn’t worth paying more (increasing the share price over) on its own because the cash used to buy the shares is worth ~5.5% today according to the risk free rate.

In fact if one were considering the dividend alone then the company should be worth less. Obviously factoring in future growth, etc… the market has landed on the current price.

Diab0lic's comment is true about future dividends - but my point is that comparing today's share price to the share price in 2000 and implying they haven't done much misses the fact that they've paid out something like $54 billion in dividends since then.

This will be wrong but true enough to make my point; With a market cap today of ~$215 billion, had CSCO not paid out dividends, their market cap would be $215 billion that represents current cash and the discounted value of future cash + the $54 billion that would also be in cash -- for a total of $269 billion. That's enough to add ~$15 to their share price.