OK Caledonian, I think it would help to make explicit your position (others too but first yours) tell me how much I have right....
1) you think that there can be philosophical progress (i.e. not the strong position being argued against above)
2) you think that progress tends not to happen in the field of philosophy (I presume because of how philosophy forms free floating ideas rather than ones ‘grounded’ by their attachment to empirical evidence)
the practical implication being that philosophy should no expect answers to some questions before groundwork is done in other areas.
3) you evaluate ‘progress’ and ‘useful’ in a different way to Richard and HA, Richard would find a interesting logical debate ‘useful’ you would ask if the logic can be used to make a car or feed the hungry or whatever. to get slightly more philosophical—maybe it is ‘empirically verifiable truth’?
4) To try to use data created by a feild you dont trust to create good data to prove that the feild doesn’t create good data seems unlikely to be unproductive (shutting the door to the ‘why don’t you argue from the literature’).
I think those trying to prohibit bad methodology easily fall into talking about it as being by its nature always useless. that people naturally do that doesn’t damn their position entirely.