that's the passenger-centric view; or, rather, the view of a passenger with status.

EI is not as sensitive to these "difficulties" (such as they are) that are experienced by their status customers (or by others who might have oneworld status elsewhere and long to have it recognised by EI too). I'm sure that EI are aware of the issue, and the grumblings - but they can probably rationalise it away as the grumblings of just a few customers. The majority of EI's customers either are not AerClub members (or not members of any oneworld programme) or have no status (in either Aer Club or any oneworld programme). So the "hardship" of a minority - albeit one that are "good" EI customers - is not something that registers to the same extent with EI as it does to those that experience these "hardships".

So again, I don't think EI is too bothered by these "difficulties"; certainly not to the extent that they will take on the additional hassle and expense of oneworld membership to sort out.

[There are certainly further steps, short of oneworld membership, that they could take. I still don't understand why there is not full and reciprocal frequent flyer recognition between EI and BA, for example. That could easily be introduced, together with similar recognition for (some/all) of their North American partners (AA, AS, B6, UA) at least for tickets that involve both carriers. Apparently, they don't even want to address this - so I genuinely don't see why EI would now pursue any kind of oneworld membership in which all of these reciprocal recognitions, and many many more, would be forced upon them, with little or no added benefit to the airline (because they already have the exact kind of working/commercial relationship with the "meaningful" oneworld members that they clearly want to have, and have no need for any dealings with the other oneworld members)]