> 4) For total compensation there seems to be two tiers of companies, the top tech (google, facebook, amazon, etc.) and everyone else. I've noticed the big difference is not the base salary (top tech only pays a few % more). The really big difference is cash bonus + stock (RSU).
This is partially true (IMHO). What the other companies provide is potentially higher upside with a lot greater risk. Younger people, or rather those with less life responsibilities, are more likely to make that trade-off. Equity in a startup might go 10x or even 100x or, hell, 0x. None of these is likely to apply for Google, Microsoft, Facebook, Amazon, etc.
> 5) Unfortunately, the interview skills required to get into the top tech companies is biased against older software engineers.
I disagree with this assertion. To be a software engineer is to be in a constant state of learning. Period. It's true that those with less life responsibilities will have more time and greater inclination to spend outside work time learning new things. I mean this in a general rather than specific sense. But that's not biased against older engineers. Those with more life responsibilities have simply made certain choices.
Put it this way: in many professions married people with children work full time and then go study part-time to get a Masters or some other qualification. It's demanding, sure, but it's a choice and it's certainly possible.
I think it's true that in Silicon Valley there is _some_ bias against older engineers. You see this in terms of starting salaries and signing bonuses for the better grads from Stanford, MIT, CMU, etc. These can be a significant percentage of what someone with 10 years experience working at exactly the same company is earning.
But life responsibilities or not, no one owes you a living. Those who invest time to maintain and improve their craft are, as a whole, going to do better in the long run. There's nothing ageist about that.