tl;dr: It’s plausible to me that the future will involve far more nonbiological sentience (e.g., whole brain emulations) than biological sentience, which might make farm animals redundant and wild animals vastly outnumbered.
You write:
The second reason is an interesting possibility. It could be the case if perhaps there aren’t a vast number of expected non-human animals in the future. It does indeed seem possible that farmed animals may cease to exist in the future on account of being made redundant due to cultivated meat, although I certainly wouldn’t be sure of this given some of the technical problems with scaling up cultivated meat to become cost-competitive with cheap animal meat. Wild animals seem highly likely to continue to exist for a long time, and currently vastly outnumber humans. Therefore it seems that we should consider non-human animals, and perhaps particularly wild animals, when aiming to ensure that the long-term future goes well.
I’m not sure why you think it’s highly likely that wild animals will continue to exist for a long-time, and in particular in large numbers relative to other types of beings (which you seem to imply, though you don’t state it outright)? It seems plausible to me that the future will involve something like massive expansion into space by (mostly) humans, whole-brain emulations, or artificial sentiences, without spreading wild animals to these places. (We might spread simulated wild animals without spreading biological ones, but we also might not.)
Relatedly, I think another reason farmed animals might be made redundant is that humanity may simply move from biological to digital form, such that there is no need to eat actual food of any kind. (Of course, it seems hard to say whether this’ll happen, but over a long time-scale I wouldn’t say it’s highly unlikely.)
tl;dr: It’s plausible to me that the future will involve far more nonbiological sentience (e.g., whole brain emulations) than biological sentience, which might make farm animals redundant and wild animals vastly outnumbered.
You write:
I’m not sure why you think it’s highly likely that wild animals will continue to exist for a long-time, and in particular in large numbers relative to other types of beings (which you seem to imply, though you don’t state it outright)? It seems plausible to me that the future will involve something like massive expansion into space by (mostly) humans, whole-brain emulations, or artificial sentiences, without spreading wild animals to these places. (We might spread simulated wild animals without spreading biological ones, but we also might not.)
Relatedly, I think another reason farmed animals might be made redundant is that humanity may simply move from biological to digital form, such that there is no need to eat actual food of any kind. (Of course, it seems hard to say whether this’ll happen, but over a long time-scale I wouldn’t say it’s highly unlikely.)
For arguments for and against these sorts of points I’m making, see Should Longtermists Mostly Think About Animals? and the comments there.