That may be the case, but consider that most consumers are probably currently using the <$15 earbuds that came with their phone. When those users switch to Beats they will get a much better sound experience, even if the frequency response is skewed.
I'll continue to recommend sennheiser over Beats, but I think the primary objection to beats should be their cost, not their quality.
This is a very important thing to remember: people always talk about how 'audiophiles' hate Beats headphones and would recommend a better-sounding, worse-looking and sometimes more expensive option.
The people buying Beats are people upgrading from their free headphones that came bundled with their phone, or the $15 ones they picked up at the supermarket.
Those are $30 headphones and I _love_ them. I use headphones 10 hours a day and it's always the apple ones. So comfortable, just the right amount of noise-canceling so I don't have to remove them to talk to people, and they sound good to me.
Beats are also very comfortable. Not much is said on headphone comfort in reviews and comparisons but it's very important for me.
I'll continue to recommend sennheiser over Beats, but I think the primary objection to beats should be their cost, not their quality.