It's not worth signing anybody older than 25 unless they're named Dzeko or Giroud (or someone else of that ilk who we're yet to be linked with). And even then... for a team with a mid-table ceiling (this season, at least), is it worth spending big for a class 30+ year old? I'm not convinced.
There are forwards who are useful today with plenty of good years left to give. If Walsh can't find any of them, add it to the list of reasons why he should fuck off.