There doesn't appear to be anyone looking into this, but a bug report has been filed for it.
See https://ask.wireshark.org/question/6892/wheres-the-wireless-toolbar/ and https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=15445
My capturing machine is Linux, currently with Wireshark 2.6.10.
On this machine the toolbar is there (although it is always hidden).
But my office machine runs WIndows 7 with the Wireshark 3.0.3. On this
machine there is no wireless toolbar to be shown.
My concern is that as soon as Ubuntu repos start serving Wireshark R3,
the toolbar will disappear from my Linux machine.
It is much more convenient to have some more control using the toolbar
than make magic in the console ;-)
Meanwhile, if you're on the Windows platform and using Npcap, you can use the bundled WlanHelper tool to configure your WiFi adapter for capturing.
Ref: https://nmap.org/npcap/guide/npcap-devguide.html#npcap-feature-dot11-wlanhelper
I haven't tried capturing on Windows with npcap yet but as I can see,
there's very little cards supported.
I some years back I desperately wanted to do it on Windows, but it was
never a vital option ;-)
--
Bartosz