The investors in these companies and all this infrastructure are not so much concerned with whether any specific companies pays off with profits, necessarily.

They are gambling instead that these investments pay out it in a different way: by shattering high labour costs for intellectual labour and de-skilling our profession (and others like it) -- "proletarianising" in the 19th century sense.

Thereby increasing profits across the whole sector and breaking the bargaining power (and outsized political power, as well) of upper middle class technology workers.

Put another way this is an economy wide investment in a manner similar to early 20th century mass factory industrialization. It's not expected that today's big investments are tomorrow's winners, but nobody wants to be left behind in the transformation, and lots of political and economic power is highly interested in the idea of automating away the remnants of the Alvin Toffler "Information Economy" fantasy.