Solutions like the Stratus ESG don't really help IFR aircraft much. RNP now really requires a C146a device - or WAAS. This is made more so by the paucity of ground based aids after the shutdowns. Either IFR aircraft will have a WAAS gps already, or most owners will face up to installing a C146a GPS in order to meet the new PBN requirements.
Stratus ESG might be a cheap way to get make a VFR aircraft ADS-B compliant, but why would a VFR aircraft bother?
The built in WAAS transponders are a solution in search of a problem.
And IFR aircraft owners remain having been raped by CASA (again)