The problem is if he wanted to leave, there's not really another option. For the moment it seems we are lucky, it's not yet the case, and we may hope to keep him this summer. But after one more season without CL, I wouldn't expect to keep such a world class player (and would be ashamed if some lunatics burn his shirt the day he takes that sadly logical decision for his carreer).
I mean would you still want to keep Luis if he becomes as disinterested as Torres in his last year, or show irritation as much as he can (and that's a lot
) ?
Then I think, the only option to be sure to keep him, is to make him *not* want to leave, and there's only one way (out of a miracle where we qualify this year), qualifying or at least showing a real intent to qualify for CL in 2013-2014 (and that means adding several proven first class players to the squad this summer, which would probably require a massive investment).
(Some would say there's also the option of increasing his wages again, but I think Luis is a competitor, not a mercenary, a new contract alone won't be enough to keep him if the team don't improve.)
So from a supporter point of view, I'd say spend what needed this summer on proven players who can directly make a difference, then we can seriously hope to qualify for CL next season and be sure to keep him, attract even better players if needed the next, and why not be competing for the league around 2015-16.
Now owners who may not want to inject that much money in one transfer window, who may prefer to buy ressellable prospects than expensive veterans, and who may even have already accepted that returning to CL may take 2 or 3 more years, may have a very different pov. If their plan is taking 4-5 more years to transform a team of promising youngsters into new Barcelona (or, more realisticly, to transform Liverpool into new Arsenal), they may be already convinced that they won't be able to keep Luis for more than one year, and may find some interest to sell him this summer instead of waiting for him to want to leave the next (with the risk that say an injury or behavior issue reduce his price in the meantime).