You're missing the forest for the trees here. In these larger companies, senior engineers tend not to work directly with code that much anymore, they're usually working on higher level problems like system design or management. These require different skill sets such as leadership and social skills that take years to develop; the ability to google quickly for a function name isn't really valued as much.
If you're working in a small company or a startup, then you don't need BigCo senior engineers, you can get away with people who haven't developed these skill sets. However if you have intentions of growing, either in your system size or in your headcount, you shouldn't discount these engineers over minor details like this. Ask them higher-level design questions if you actually want to test their abilities, otherwise you're looking at the wrong metrics.
Depends on where you go. In the Big Tech cos, you usually have this hierarchy:
1) Junior Engineer - can write basic code, but usually needs help for bigger projects or navigating a code base.
2) Engineer - Is pretty independent and can whip together what they need based on a design.
3) Senior Engineer - Can take a problem and build a design for it, can lead a team of lower-level engineers to properly implement the design.
There are higher levels like staff and principal engineer, these ones typically are the same as senior engineers but are at larger scopes.
At levels 3 and higher, you tend to write more English than code. You're there to decide what code gets written, rather than the specifics on how it gets written. That's what levels 1 and 2 do, they'll take your designs and implement them.
That's fair. No sense in bringing in architecture astronauts who can't translate their dreams to reality.
> we let you Google whatever you need in the interview
Right, rejecting someone who can't Google things properly is the correct choice. That's a skill that's useful at all levels.