I'm pretty sure Amber and Liz are primarily there for the swimming scholarship.
From what we know, Amber had applied to the school first, and not on swimming scholarship, so i don't think it makes any sense to presume swimming was her goal. She certainly never attempts to get swimming scholarship for herself. Liz has followed Amber, and she did it by acquiring the swimming scholarship, but it was her mother's idea she simply humored, because she thought it'd give her opportunity of doing two things she enjoyed, swimming with Amber and training. Neither of the girls has any actual interest in making swimming their career.
Maybe not Amber on paper, but what else is she going to do? It's not that she HAS to do swimming, it's that it's ludicrous NOT to give an opportunity to her AND her sister to be in a special situation for a POTENTIAL swimming career.
There's nothing ludicrous in not wasting time on a thing that gets in the way of things they're actually interested in, and little sense in aiming for a potential career neither of them wants that's going to be over in a few years. They can instead spend this time learning and honing the skills to get good jobs with long-term prospects that they might actually want, after their education is complete.
"But they can quit anytime if they want". Sure, and will your MC kill Erik the moment they do, or does Erik effectively get out of this whole ordeal not just scot-free, but with all profits from his sponsorship he'll make down the road? Because that's effectively what MC's "blackmail" gets him. Oh, he won't be able to rape two girls he's sponsoring, that he wanted to rape. What a terrible and just punishment. That will sure teach him.
I feel there is a reason our first individual meeting with Liz is when she's swimming, lazy as she, if there is one thing she can "tolerate" it's swimming. And Amber towards the end of their arc was very happy competing against Liz in a friendly manner, why not do that swimming rather than flipping burgers at a fast food chain?
Liz names few other things she'd be fine doing instead of swimming in her epilogue. And what makes you think there's any need for anyone to flip burgers if the sisters don't get into professional swimming? Amber has her regular, full scholarship and Liz is more than capable of acquiring/maintaining one as well, between being the higher achiever of the two and MC's ability to blackmail the dean.
If you mean flipping burgers as something to do
after their studies are finished, then i'd really have to wonder what makes you think that a graduate of the most famous university in the world, which is said to pretty much guarantee these who complete it excellent jobs, is going to wind up flipping burgers. Perhaps because it's quite harder to sell swimming as viable career when the alternative isn't flipping burgers but top positions in R&D, business or other respectable fields?
And with the way Lucy didn't want to lose the job when she met us as our Hero Form; you REALLY think she made up a sob story to defend E.R.I.K?
I really think it's quite likely she's never looked all that hard for possible alternatives. Because why would she, as long as she was already getting the money she needed? So she wouldn't have to turn blind eye on her boss being a rapist and murderer? That ship has already sailed.
And I feel like you didn't even read what I said about the cancer treatment. Give everything I literally just said, he was paying for it, that's how blackmail works. You don't suck dicks you don't like for no goddamned reason.
Plenty of secretaries suck dicks of bosses they don't like, simply to keep their jobs, not because they have dying children. It doesn't even mean they get paid any extra for it, just that they keep the job and get paid at all.
It's a simple scenario: Lucy gets a work as Erik's secretary. It's relatively well-paid job (he is a CEO) so she's happy with it. Then after a while Erik tells her she either provides him with sexual favors or he fires her. Perhaps because he knows about Lucy's daughter and that Lucy is in a hard spot. And Lucy figures she'd rather suck that dick and keep her job than spend weeks or months without income, trying to find another work that'd pay her similarly well.
What universe are you living on, where even INSURANCE let alone a secretary position pays for cancer medical treatment in one of the most expensive regions? Unless she's working for Elon Musk personally, or shining Jeff Bezos's shoes, even then she's not going to have the pay to upkeep on cancer treatment, that's not how secretary pay works.
It may shock you to hear this, but cancer treatment on this very planet, in this very age, is performed free of charge in public hospitals in EU and other civilized places. That's what universal healthcare gets you. So that's kinda why i can't help but roll my eyes at this supposedly unsurmountable task poor Lucy is facing in the world which has advanced far beyond ours and which supposedly puts extra effort in equal treatment of all its citizens.