I have only provided a quote from the interview. this is the Canon's take on the subject. I read this as follows: IBIS is considered a PRO level feature in Canon Universe and is therefore reserved for a higher, PRO level body that event shooters and PJ's would use. 5 series camera body level comes to mind.
My takeaway from this interview: the lack of certain features in R was a business decision rather than an inability to deliver a viable technical solution.
Oh, fair enough.