Simply put, he also doesn't have the upside that Belly has.
The Jays need to do their homework here and see what the chances are that Belly's regained the flexibility he needs to regain his stroke. This is similar to what happened with Chapman last year. He was further removed from his surgery and this allowed him to return back closer to the player he was in 2018-2019. Did the Jays know something the A's didn't? Did they just get lucky? Who knows.
But of course, if it was obvious Belly is regaining the tools he needs to be a good/great hitter again, then the Dodgers tender him - so there's probably a very good chance he's still hampered and unlikely to bounce back at the dish. Or maybe the answer is that nobody knows - or the Dodgers weren't ready to risk that he'd get there with another full offseason of work. Given all the advancements in swing training, you'd think someone with the talent of Belly would be able to work his tail off and reinvent himself at the dish. They have all the ability in the world to prove if they are getting the right results.
This is a very interesting development to watch this offseason and into next year.