I'm pretty sure the Buddha encouraged meditation, vipassana, and jhana. So if there was a meditation technique based on the four foundations of mindfulness, that led to insight, I don't see why he would discourage it (Obviously there can be specific cases, even a majority of the time at least in theory, where certain types of meditation would be less appropriate).
Then there is the sutta (I believe it is in Bhikkhu Bodhi's anthology, and therefore elsewhere, too) that talks of 4 ways his disciples progress: insight preceded by concentration, concentration preceded by insight, the two together, and the last I think is someone who after a while loses confusion regarding the dhamma.
Also, as for there not being mention of attaining stream entry in meditation, it's interesting, but there is mention of many techniques, or at least six or seven, that lead to the deathless (food, body, death, inconstancy in conditioned things, suffering in conditioned things, what else?...), suggesting that these contemplations can lead to stream-entry.
I'm not sure that Goenka is of the opinion that jhana is not fruitful, but I think that jhana is discouraged during his retreats (at least the "normal jhanas"). This might seem silly, strange, because the Buddha encouraged jhana. But I'm not sure it is silly or strange. The Buddha also encouraged metta. Yet if one's main meditation object is the body, it might make sense to tell oneself "Okay, don't focus on metta, now you're going to be mindful of the body." If metta arises during mindfulness of the body, okay, but still one stays mindful of the body, not switching to cultivation of metta. Maybe a person could do both, but many like to stay to one technique at a time. In the same way, a person might say, "Okay, don't focus on jhana, now you're going to just observe ("[just observing]" sensations being a common instruction in Goenka, no?)"
I mean, I don't know, but if a person went into a jhana during a Goenka retreat I don't think the take on it would be, "That's not the instructions," but the take might be, to just keeping being mindful... if a sensation crops up, it crops up...