You may be right... but "Siri" itself is a riff on "SRI", as in "Stanford Research Institute" or "SRI International".

Apple could use their money to try to take down an open source university project, which would certainly foster goodwill for them, and it would probably draw attention to Siri's DARPA roots, which would also be some doubleplusgood publicity for them.

They might be better off just not spending the money and buying back more of their stock.