That sounds like the "not real communism" argument. "Not real sharia". I would argue that SA is absolutely real sharia, and they have schemes to allow mortgages that function basically like lending but avoid mechanisms that would look like lending for profit by the letter.
The problem with rules against lending for profit is that you have no incentive to let anyone use what you have for their own benefit. If someone comes to me with an awesome business plan and wants some money, if I want to help them I am going to expect them to take the risk on their business plan rather than subject me to it.
What's SA? Saudi Arabia I presume? Are you a scholar to argue what is and isn't compatible with Islamic laws? We go back to our texts (Quran, Hadith) to determine whether something is or isn't compatible with Shariah. There are explicit texts that prohibit increasing the price of an item in exchange for a delay in payment.
> you have no incentive to let anyone use what you have for their own benefit.
Renting is a trivial counter-example.
> if I want to help them I am going to expect them to take the risk on their business plan rather than subject me to it.
Which is specifically one reason why lending with interest is prohibited. You don't get to profit off of the need or misery of others. There's a power dynamic difference that Islam aims to make more even. We've already seen countless times how this ended up throughout history. And we're living it today.
I'm not a scholar, but I'd guess that the Saudi government consult scholars and their government is probably more knowledgeable than either of us on this topic. You discredit their rules by claiming that they were installed by the west (which does not matter, either they follow sharia or they don't) and then appeal to scholars. Sounds to me like you want your idea of sharia and anyone who disagrees "needs to consult a scholar".
I've always disliked this appeal to scholars in Islam because Islam likes to set itself apart claiming there is no pope or interpretive authority on the law of God and then any time a person has a disagreement they appeal to an authoritative priesthood class to stifle discussion on issues that matter. For a religion that bills itself as easy to understand by the common follower of the religion, deference to human beings as authorities are quite common.
The problem with rules against lending for profit is that you have no incentive to let anyone use what you have for their own benefit. If someone comes to me with an awesome business plan and wants some money, if I want to help them I am going to expect them to take the risk on their business plan rather than subject me to it.