Failing to meet people's needs is definitely a problem, but not a uniquely market-driven one. If there is a specific phenomenon which causes markets to fail in the delivery of socially desirable goods, it would be good to come up with a specific description and corresponding term of art.
> 'Market failure' is a term of art, and it's generally best to avoid redefining terms of art unless there's a very compelling reason to do so.
The person conflating "market failure" with what they were talking about is the GP.
The original comment was about the market failing to accomplish a goal, which is a perfectly idiomatic usage.
>"... they'll never think a failure to meet society's need is a market failure..."
If they only meant to talk about "market failures" as such, then they are guilty of pedantry