[Seniority, familial relations and (ahem) gender mattered more during those times, IMHO.]

I certainly agree with this and think JA would have regarded "obedience" as a generally desirable quality. It's a concept we can find a little alien from our position where women value their independence. It's only in more recent years that the Church of England marriage service made the use of the word "obey" optional.

In Chapter 19, when Mr Collins is about to propose, Lizzy tries to leave the room, but when her mother insists that she stay we are told that "Elizabeth would not oppose such a direct injunction." This is surely because disobedience to parental authority is not seen generally as the correct way to behave. The issues JA raises are more, I believe, centred on whether those in a position of authority use their judgement wisely (as of course Mr Bennet does when he refuses to insist on Lizzy marrying Mr Collins.)
IMHO P&P spends much time examining the use and misuse of authority - especially parental. Darcy is in loco parentis to Georgiana and in this and other incidences is shown to be instructing and guiding her with firmness, kindness and love - and this behaviour is intended to play a crucial role in increasing the reader's (and Lizzy's) respect.