Thanks for the details. I will check out the link. I should say that "real advances they were after" is not at all incompatible with "made it mainly to please

Thanks for the details. I will check out the link. I should say that "real advances they were after" is not at all incompatible with "made it mainly to please themselves". The things that pleased them may well have been "real advances"; they often are. The question is the extent to which they were prioritizing the needs, capabilities, and interests of the whole audience being served, not just the things they personally thought important or preferable.