I don't disagree, but not typically an option on quick one-man-band shoots. For sit down interviews i'd like to add a stand I can swing a boom on so I can feasibly be behind camera and mic, be able to move both without needing to worry about one going completely awry while I operate the other.
Can you expand on the Sony option?
You can get URX-P03D UWP-D two-channel portable receiver.
And use it with UTX-P03 UWP-D XLR plug-on transmitter for microphones that require phantom power (eg. your AT875R).
And with UTX-B03 UWP-D belt-pack transmitter to get lav system that you wanted.
Or UTX-B03HR UWP-D body-pack transmitter to add hirose connector lavalier of your choice.
Finally, UWP-D Series system has line input available for added flexibility, if you want to add Sound Devices MixPre-3 latter (which you can remotely control via Wingman app.).