I think "put up with complaining it can be slow to do inefficient analytics queries" is why I would rather pay for some 3rd party tool that would get the complaints.
Business people want some queries that are slow no matter what you do. Then expect these to run in under a second. They don't care about some abstract things like operations complexity or big O - they want it here and now.
Even if your data fits on one server there are still queries that will take time and it is not going to be instant, even if you put whole db in RAM it is going to be fast but still I can imagine bunch of queries that will simply have to take couple of minutes anyway.
Business people want some queries that are slow no matter what you do. Then expect these to run in under a second. They don't care about some abstract things like operations complexity or big O - they want it here and now.
Even if your data fits on one server there are still queries that will take time and it is not going to be instant, even if you put whole db in RAM it is going to be fast but still I can imagine bunch of queries that will simply have to take couple of minutes anyway.