The lack of movement on Karlsson had more to do with San Jose not wanting to retain much - or any - salary on Karlsson, who still has 4 seasons remaining after this one at $11.5M per season. Reports from earlier in the year indicated that Sharks GM Mike Grier was only willing to retain $1M, less than 10% of Karlsson's contract.
On the Ekholm side of things, the Predators only ended up having to retain 4% of Ekholm's $6.25M salary to push the deal through with the Edmonton Oilers. He remains signed through the 2025-26 season.
Friedman stated that, while the Leafs were very high on both players, the money simply didn't work, given how little the Sharks and Preds were willing to retain on Karlsson and Ekholm. In the end, they were able to get McCabe at 50% of his original $4M salary. He's now on the books in Toronto for 2 seasons after this one at a very modest $2M cap hit.