PSG is a very strong club financially but no matter how financially strong PSG is, they never want to lose money on player transfers. If a player moves to another club, the fee PSG receives for the player's transfer is a profit and PSG will never give it up. PSG spend huge amount of money to buy world class stars but due to their main focus on only world class stars they forget that world class attacking line up needs world class defense and midfield line up. If they hadn't forgotten this, they would never have bought world-class stars, they would have bought world-class stars and quality midfielders and defenders to make them a complete team. PSG is a team that has always failed in this perfection.
I agree with you but it is totally normal. I think none of the richest teams would like to lose a lot of money in transfers. This is why they are trying their best to keep Mbappe for one more season now. Mbappe's being sold in the previous transfer window was their priority. Because he wasn't keen on signing a contract extension.
However Mbappe just wants to stay for his last season with PSG and then leave. Otherwise PSG would have still made a serious profit in his transfer to Al-Hilal. PSG signed him for a record price back then and I understand them about not wanting to lose him for free.