Trophies always matter, but being phenomenal in the CL or EC/WC and not winning it, can enhance a legacy to heights previously unseen, too. Puskas, Eusebio, Cruyff, Platini and Zico '86, Zidane ('06 k.o. stages, Brazil especially), Gascoigne, Baggio and so on and so forth have benefitted in this way.All Messi needs to do to further enhance his legacy is to play really well. At this point in his career, trophies doesn't matter anymore, if he hummiliates chelsea players and barça gets knocked out anyway, people will still rate him very highly.
Ronaldo continuing to perform in the CL as he does means Messi must, too. Things would be different if Ronaldo wasn't around, but he is.