Yes, 400k is easily attainable as an L5/E5 at FANG. That's 200k base salary, 30k annual bonus, and $175k yearly RSU vesting (or about 750k initial grant). Those are definitely possible. Staff-level (L6) is about $250-300k, $50k bonus and $300k yearly vest at FANG. Senior engineers at Netflix make $600k or more per year in base salary only.

I'm not smart enough or ambitious enough anymore for staff but L5 is definitely doable.

Is Google really that much of a jump from L4 to L5? Their L4 packages are reportedly in the ±270k area (and my offer last year was well into the minus part of that range).

Also, and possibly related if the point above is the case, I have read from various Googlers recently that getting hired from outside at L5+ is really hard.