PT18 · S4 · Q8 In Malsenia sales of classical records are soaring

If this were true, it would somewhat strengthen the author's story that people just want the experience of hearing this music at home, as they do when they're hearing it on a televised commercial or sporting event. But the author doesn't need this to be true. If you negate it, the answer says "there is at least one classical record that sold well in Malsenia that didn't include any familiar pieces from TV". Since that wouldn't hurt the author's argument, this can't be a necessary assumption.

This argument was never discussing the quantity of concerts, just the attendance of concerts. If we negated this answer, it would say "the number of classical concerts has decreased in response to smaller audiences". That wouldn't hurt the author's argument in any way. (We could have made quantity of concerts relevant if we thought of it as an alternate explanation for low audience size --- if you suddenly tripled the number of concerts you were holding, that might spread out the people who attend concerts such that there are fewer people per concert, sort of like when LSAT changed from offering the test 4 times a year to 6 times a year, they will have fewer people in the audience for each test administration, even though the number of people who desire to take an LSAT hasn't changed. A correct answer could have been worded "The number of people at concerts has not been greatly diluted by a decision to hold many more concerts than before")

Does it make any difference whether the classical records are studio albums vs. live concert recordings? The author's argument isn't that "people like that clean, tight studio sound, not the airy live-concert sound". Her argument is that "people want their classical music on recordings, not in person". Listening to a live album is still listening to a recording. If we negated this answer, it would be saying that most of the recording are live-concerts, but that would probably only strengthen the author's argument, because it would suggest that people like the sound of live concerts but still aren't attending because they prefer to listen to it on a recording.

If we negate this, we'll be saying that the live concerts are limited to music that is readily available on recordings. So would that be an alternate explanation for why audiences at shows are decreasing? No, it would sort of just stay compatible with the author's explanation that people like the music but have no desire to see it live.