Good ideas aren't worth much if the business model doesn't work. They've raised over $100M and have pivoted multiple times. At some point you have to ask whether the idea is not a feasible one.
Alternate possibility: the core idea is a good one, but they raised too much money. Now they have to live up to an impossibly-high valuation and can't just be a blogging platform.
Alternate possibility: the core idea is a good one, but they raised too much money. Now they have to live up to an impossibly-high valuation and can't just be a blogging platform.