Anyone who thinks Elizabeth is 'shallow' isn't considering the Charlotte Lucas subplot which Austen sets in deliberate counterpoint to Elizabeth's.
Marriage was the only career open to the Bennett girls, who have minimal education, mostly in 'accomplishments' intended to add to their marriageability, and live in a world where the only work open to impoverished women of their class is the genteel live-in slavery of governessing or acting as a paid companion, like Anne de Bourgh's companion or Miss Annesley, Georgiana Darcy's companion.
Charlotte and Elizabeth are doubles in many ways, clever single girls in large families without a lot of spare cash -- the differences are that
(1) Charlotte has brothers, which means their home and estate is safe for the next generation, so that she will at least have a home with whichever brother inherits, albeit as a spinster hanger-on and
(2) Lizzy is pretty, and 20 to Charlotte's plain 27, which means she has a far better chance on the marriage market, despite her lack of fortune and her family's drawbacks.
She has enough assets to hope to do better than Mr Collins, but for Charlotte, plain and ageing, and primarily wanting her own home, he's a fabulous opportunity. Lizzy falls hard for Wickham (something that tends to be glossed over in adaptations), but her prudent aunt points out that he's far too poor to marry, and Lizzy acknowledges the truth of this and backs off, only to see him run off after an heiress.
Marriage has been an economic decision in the novel long before Lizzy sees Permberley -- and as well as Darcy's wealth, what she falls for there. even before she sees him, is the restrained good taste of the house and grounds, the evidence of him being an excellent landlord and a kind brother, rather than the joyless, arrogant man she met at home, and whose first proposal was all about how he knew he was too good for her.