Let me spell out the analogy:

Gladwell says you need practice 10,000 hours. In my analogy of the situation, I claim I need 500g of flour.

You complain that there may be other things needed in addition to practice therefore the need for practice is bullshit. This is analogized by "you" saying that the need for other ingredients in bread somehow invalidates that the flour is needed.

The point I'm trying to make is this: Stating that something is necessary but not sufficient, does not invalidate claims about what is necessary. In the quotes, I saw no claim that only 10k hours of practice was required, just that they were necessary.

Don't get hung up on the number. I've always taken Gladwell's writing to mean lots of deliberate practice (on the order of a decade) is necessary, but maybe not sufficient, to master something difficult.