But when you buy software, you aren't usually buying the software, but rather a license to use the software
What dirty, dirty, lies! I can tell you for a fact* that I have never once personally licensed software despite purchasing several valid copies. I have four reasons for saying this:
— First, having a debugger installed on my PC means I can modify the installer [while running] to show no EULA at all, so further proof is required I have agreed to whatever blatherskite the software publisher is trying to push.
— Second, I have never been presented the EULA terms before paying for software, so all claims the transaction was not a sale occur ex post facto.
— Third, I have never given my money directly to the software publisher, but to a retailer such as GameStop, Amazon, or Best Buy, so the publisher becomes a "third party" to this transaction and lacks any legal standing to decide its' status.
— Finally, because US copyright law allows me to make copies as "an essential step in the utilization of the computer program" and one copy as a backup (see Title 17 section 117), I have a pre-existing right to install the software; the typical EULA therefore grants no quid pro quo to me and therefore is contractually void.
Disclaimer: This is not legal advice, I am not your lawyer, and in fact I am not a lawyer at all! I do play one on ... I mean, work with them every day, and several of them have agreed that the above arguments are strong enough that certain other people would lose sleep at night should I ever find cause to argue them in a courtroom.
[[*: This is hyperbole, really, although I suppose you could say it is "pending legal review". I don't feel the need to go beyond what copyright law permits... and that's pretty much what a typical EULA asks anyway. Until there's sufficient harm in the divergence between my interpretation and the demands in the EULA for any software I have purchased, I have no reason for me to actually test these arguments in a court of law. So far I've skirted this by avoiding really problematic publishers, but I fear the day of testing is fast approaching.]]