I really hate when people say that when you know just as well as I do that Apple will shove the update down my throat. My MBP is six years old this year, and is very much showing its age. I will be purchasing a 2012 MBP shortly after release, out of necessity. I don't know whether it will come with Lion or ML, but from what I'm reading, either way I don't want it. I do not like iOS that much.
So you say "purchase an early 2011 MBP that runs SL," and I would do but I can't expect that'll last me more than six years either (and it's already a year old). Really, as far as I can tell, my best option is to Hackintosh SL onto my Mac, which seems a bit ridiculous.
So my point: don't just go around saying "Then don't upgrade!" when you know as well as I do it's not that simple.
Unless you truly need any of the hardware changes in a refresh - most people dont - then you have a simple choice to make. Upgrade and adapt, or find an older model and deal with the consequences of making that decision. Apple does not shove any updates down anyone's throat.