I don't know if people have really talked about this here, but it seems for a while now, Apple has discontinued the Thunderbolt 1/2 adapters for Ethernet and FireWire, as part of slimming down their product line by eliminating anything outdated (they even finally discontinued that USB 2.0 external SuperDrive). They still make a USB 2.0 to Ethernet adapter, but nothing for Thunderbolt. For use with modern Macs, Apple now directs you to third-party USB-C to Ethernet adapters. Nothing for anyone still using FireWire devices (as long as they still work and get the job done!) but if you already have the FireWire to Thunderbolt adapter, Apple still makes their Thunderbolt 2 to 3 adapter to daisy-chain to. (This is what I'm currently doing at my college for digitizing the TV studio's Video8 and Hi-8 library via my Sony Digital8 camcorder hooked up to one of our M3 iMacs.)
Though I wouldn't be surprised if some third-party company starts making a FireWire 800 to Thunderbolt 3 adapter in the future, thus avoiding the need to daisy-chain the Apple ones or get an expensive Thunderbolt dock that may have a FireWire 800 port. (And it'd be good for Windows users with some kind of PC laptop or all-in-one with a Thunderbolt 3 port or greater.)
Though I wouldn't be surprised if some third-party company starts making a FireWire 800 to Thunderbolt 3 adapter in the future, thus avoiding the need to daisy-chain the Apple ones or get an expensive Thunderbolt dock that may have a FireWire 800 port. (And it'd be good for Windows users with some kind of PC laptop or all-in-one with a Thunderbolt 3 port or greater.)