I’m a bit skeptical about this claim. I’ve been following eWeLink-compatible devices for quite some time, and I haven’t seen established third-party manufacturers competing for an “eWeLink certification”. The non-Sonoff products I’ve encountered with the eWeLink Support label were mostly AliExpress white-label devices, Sonoff-like clones such as Woolley, or products from companies closely connected to ITEAD/CoolKit.
If this is really the reason for the decline, which manufacturers or products have actually left eWeLink because of these increased costs or requirements?