My view is that it isn't really entirely about economics anymore at least on a traditional cost/benefit analysis basis. It is seen as a way to disrupt industries. Think of it more like war with arms race dynamics (winner takes all), or consolidation of power to capital over labor. Even if it is a net negative you need to play to stay in the game even if it disrupts your own revenue (e.g. Google) else lose entirely.
I suspect the capital class would throw good money after bad to make AI viable especially since a lot of the costs are fixed in nature (i.e. in training runs, not per query).
Hope it's worth it.