Canadian air traffic controller here.

ADS-B mandates are on the way. Originally scheduled for February this year for Class A and B, the first mandate has been pushed back into this summer. Classes C, D, and E mandates are now "no earlier than 2026". The original dates did not, so they say, give enough time for aircraft owners to procure and install avionics.

As a controller, I like ADS-B. My job is a lot easier and safer when I can see where you are, whether IFR or VFR, and I can use rules that are much more efficient with any kind of surveillance (Radar, Mlat, ADS-B, whether ground or space-based), meaning fewer delays. Radar antennas are spread pretty far to provide optimal coverage, but leave holes, especially at low altitudes. Your 7700 squawk could go unnoticed of you're low and fast enough from a radar site. ADS-B fills many of those. Safety and efficiency are improved immensely, even if you're not in communication with ATC.

If I had my way, everyone would be using it already, but I understand costs and availability are issues. I can be patient and continue to issue holds as needed for those low-density airports.

Edit: Antenna diversity is still required. Downward-facing-only isn't good for satellites looking down from above and there is simply far too much countryside to cover with ground-based infrastructure.