Sometimes, microtransactions are necessary. No one can be faulted for adding honest microtransactions to a finished game (though it is debatable if SoT is a finished product.) That said, Rare takes advantage of some quirks in math and in human nature.
(By the way, things can be overpriced without being immoral. That ship set could cost $4000, it wouldn't be immoral , just overpriced.)
One cannot buy things using their actual money. No, first you must pay the middleman. You can only buy things using Ancient Coins. This is a classic scam. Say you're sold on getting a parrot (edit: and the garbage that goes with it), so you head to the emporium. Your 2 cheapest options are 150 coins for $2, and 550 for $6. There is no clean way to get the 650 you need. You'll have 50 left over, which serves 2 purposes for Rare: First, you paid more than you should. Second, you've got these extra ancient coins just sitting there. Doing nothing. It's not enough to buy anything, but why let those coins go to waste? Why not buy a few more and grab another item, just so you don't have any coins left over? The 650 for a pet is just an example, there's countless instances this will occur, now and in future batches of microtransactions.
If Rare was being honest, they wouldn't have a middleman. You would just buy your creepy pets directly with real money. Or, if a middleman really was necessary (it's not), why not have smallest denomination conversion? 1 cent for 1 coin, so you always buy exactly what you need. But Rare didn't do this, because if they manipulate you into having extra coins, they can get more of your money.
There's also limited time deals. You better buy this monkey now, dear consumer, or it will cost you more later. Most people already know why this is a scam, so we'll move right along to the Magnum Opus of scammy microtransactions: Pets.
Virtual pets are disgusting. They are the epitome of manipulating people to buy crp. They take a genuine, real life affection for pets that people naturally have, and perv* it to some sickening connection between a consumer and a product. The best way to get people to buy garbage is to get them emotionally invested in it. This practice is worse than lootboxes. I'm sure you'll be able to buy little hats for your monkey and have your parrot do a cute dance soon enough. All to get the consumer subconsciously invested in, and thus paying for, a virtual item designed to feign love.
If you look at reddit, you'll see posts and art people have dedicated to their pets. On day one, people are already emotionally invested in them, and making the post will only make them more invested. These posts also encourage others to purchase a pet, or get more invested in the one they already have. And then, when Rare adds in whatever new garbage you can get for your pets, people will buy it because of their investment. Not only that, but paying for something will also get people more invested in whatever they bought, in a subconscious desire to justify their purchase. It's a self reinforcing cycle; If you devote time and money to X, you become more invested in X. If you are invested in X, you will devote more time and money to X, and so on. Rare knows this, and now they've got a good chunk of players emotionally, and hence, financially.
I understand microtransactions in SoT. I'm not opposed to the idea. But this is morally reprehensible. Rare can make extra money without taking advantage of you. Does a company that tries to manipulate you deserve your money?