Celtic are crashed out of Europe on Tuesday night when they lost 2-0 at Lazio in a Champions League group game.
The Bhoys have no chance of finishing third in their group as well, which could have got them into the Europa League knockout rounds.
Brendan Rodgers insisted after the game in Italy that Celtic need more quality to do better in Europe, but Walker does not believe that his former club will fork out the sums needed to bring in the level of players the Bhoys boss wants.
He stressed that Celtic are modelled on dominating in Scotland and he does not see how their poor record in the Champions League gets better in the coming years given the way the club are run financially.
Former Bhoy Walker said on the Go Radio Football Show: “The idea of Celtic going out to spend £10m on a player, I just can’t see them doing it.
“I honestly think that they would regard it as a false economy, it would be a player or two on exorbitant wages and it might not work out.
“You look at some of the other teams in the Champions League who are spending hundreds of millions and not really getting anywhere.
“That’s why I am saying that Celtic are a club that are modelled on trying to be dominant domestically, but as far as the Champions League is concerned, you look at the record, it’s woeful and a little bit embarrassing.
“I don’t see it getting much better any time soon.”
Celtic’s last group game against Feyenoord has little consequence for the Bhoys, who will not be involved in Europe after Christmas.