[gottago]

Not exactly unique to ITVX, a few other programmes made for Prime/Netflix (and no doubt Disney+ in due course) will appear outside of the streaming services.  All exclusivity in this regard probably means it is exclusive, but for a limited period (much like in the 90s when home video released stuff that wasn't shown on TV - most of that was eventually shown years later).

I don't think I've ever seen anything on Netflix listed as a "Netflix Exclusive". Netflix Original and Series maybe but not Exclusive. 

My point is that they launched this service as having series appear exclusively on ITVX for up to 6 months and are marketed on the service as an "ITVX Exclusive". After those 6 months it would air on ITV's linear channels, at which point it simply isn't an "ITVX Exclusive" by definition. A Spy Amongst Friends has now aired on ITV1 but go on the website and it's one of the main shows on there and it's still listed as an ITVX Exclusive.

Yes I probably am overthinking it!