Why is it bad to have 70B in cash

$60B, but, who's counting.

The fact that they have that much cash means that they cannot find anything that would materially affect their stock value (ROI for the investor) greater than the expenditure.

If they acquire a business, it needs to provide a greater return than the cash it took to buy that business. This is a problem Google and Cisco and a number of other companies face as well. Cisco's answer was a dividend - which was a sad statement for the tech market.

Google can buy all of the companies for tens of millions it wants for the foreseeable future, but, none of those companies materially affect the ~94% of their revenue brought in through search. That's why Google can be all over the board with Solar projects and alternative energy and self driving cars, etc, but, at the end of the day, will any of those ideas provide the same ROI as search?

Sure, something will come along that will do it, but, holding the cache horde right now until something encouraging comes along is slightly better than paying a dividend and having to borrow when they do find that investment they've been on the lookout for.

And Apple's stock price reflects their cash position. Don't think Wall Street doesn't analyze that and use that as a basis for assigning value. If they announced a dividend, the share price would jump to the current price + the expected dividend, then would settle back down to the appropriate valuation.