$180k+ isn't inconceivable, but it's certainly approaching a salary range typically reserved for Architects and team leads (in my experience).

It's fully realistic for non-management senior engineers to earn up to $150k, however.

We really should be talking about total compensation, not just cash salary. $180-250k isn't unreasonable cash+%+bonus for a sales engineer or consultant who puts in huge hours, or for a senior developer with bonus/stock/etc. I think a lot of people at Google end up hitting $180-200k based on total compensation once they're at the 5-10 year of experience tiers.

Right, 180K for any developer is high (hence the double-to-triple estimate). Not inconceivable for an architect or manager though in certain companies, which is a possible career path for any developer.

So how does a senior engineer graduate to architect?

He applies for an architect position at another company.