I think you're putting too much emphasis on any airline's considerations of its status passengers travelling in Economy at the very edges of (or, perhaps, even outside of) their actual network; they're not as eager to have "wall-to-wall" status coverage (meaning status pax in Y get status benefits EVERYWHERE) as much as they are eager to broaden their network just so they can sell more tickets to new, previously unreachable destinations. The airline is primarily interested in accessing destinations of interest, i.e. being able to sell tickets that get its pax to that city; it does not automatically follow that they want to ensure a status pax in Y can obtain all possible status benefits at all such locations. Great if there's an alliance partner there - the benefits will therefore be "automatically" observed - but that doesn't mean that any airline will only ever countenance offering a destination not in its own network if it can be accessed in a manner that means status pax travelling in Y can and do obtain "all" benefits. The majority of Y pax do not have status, and the airline is more interested in getting customers to as broad a range of destinations of interest as possible, rather than only offering tickets for sale to destinations for which its few status pax who might be travelling in Y will be treated as such.

Jeju was perhaps not a great example - it's not a destination offered by the ITA website, and looking at bookings made on the LH.com website for FCO-CJU, the last leg is always on Scoot so there would be no alliance benefits anyway



I'd be more worried about potential complications and issues with AZ passengers travelling to/within the US. Maybe Delta won't want to prolong any sort of partnership - though of course it also might not be happy at the possiblity of losing access to many Italian cities, but I think going forward DL/AF/KL will want to boost their own presence in Italy rather than rely on AZ codeshares, and I doubt DL would worry too much about having their pax connect in CDG or AMS to AF or KL to get to their Italian destination rather than having them connect in FCO to AZ - and it may not be easy for AZ to arrange for alternate lounge access to LHG and/or United lounges at all US points - in some airports AZ may find itself in the "wrong" terminal, and/or United may not want to step up just yet, with such a long wait until *A accession - so there may be scope for a considerable worsening in the experience of AZ status pax flying in Y to/from the US.

In any case, ensuring that Economy passengers can obtain status benefits at the far extremes of the network appears to me to be something to sort out later; it's not a Day-One priority. For now, AZ will need to be integrated into the LHG and there is plenty of work to be done in setting up those core networks. If we were to use the analogy of colouring-in, LHG and AZ are now furiously concentrating on the centre of the image, and ensuring that as many of those large, blank central areas are coloured in correctly ASAP. It's only later on that they will get to the fine detail of carefully colouring in the very margins, using fine pen strokes to bring the colour right up to the lines.