St. Clair will eventually get its fair share of densification between Keele and Jane, possibly enough to justify extending the streetcar to Jane Street, if not Jane Station. That alone would cost well north of $100M in 2024 dollars, would likely require the City/TTC to go it alone funding-wise, and is still a long way off. Extending the Dundas car to meet it at Jane would be nice for network connectivity/redundancy, and if you get a future GO station at Jane/Dundas/St. Clair on an upgraded Milton (or future Midtown) Line then you're really in business.
But honestly I don't see how going all the way down to Bloor adds enough to the network to justify spending the hundreds of millions of dollars in public money (and that's a conservative estimate at this point) for this ahead of far more pressing work, especially absent provincial or federal funding. And that's assuming the idea of a Jane LRT is dead forever, which would otherwise require the same right-of-way while using different track gauge and thus entirely preclude extension of the legacy streetcar network down to Bloor.