The edge drivers run on the hub, not on the individual devices, so there shouldn’t be any need to update the firmware of a Z wave device just because the hub is now using an edge driver instead of a Groovy device type handler. So I’m not seeing the transition to the new architecture as being something that changes the fact that smartthings has never offered OTA updates for zwave devices and it’s always been annoying that they have never offered it.
That said, because of the independent third party zwave specification, it should always be possible to update the firmware on any Z wave device with a different Z wave controller which has been added as a secondary to the smartthings Network. And, indeed, people have done that for 4 or 5 years, most commonly using an Aeotec USB stick or something like the z flash from Homeseer. You can find these options discussed in other forum threads.
Doing it this way requires several things:
One) the device manufacturer has to release their update Files (some do, some don’t)
Two) the customer has to acquire a device that can be used as a secondary Z wave controller
Three) the customer has to follow the instructions for that device to individually update any device that needs the firmware update.
It works, it’s just tedious and annoying when this is a built-in function on most certified Z wave primary hubs. 
See the following discussion thread from 2017 (!) the issue was discussed at length with a smartthings engineer, the third-party alternatives are also discussed, and as far as I know, none of this has changed one way or the other with the introduction of edge drivers.
Support of OTA firmware updates for Z-Wave / Z-Wave Plus devices