Because Oracle comes to any country/industry with trucks of money to corrupt officials and lobby their adoption.
And after a few years you find yourself in a situation when you already paid for Oracle so much, integrated it so deeply, so switching to any alternative is a massive pain and in most cases it’s safer and easier to keep paying Oracle.
I believe this is how they grew and how they remain big. While smaller companies aim for managers, Oracle targets CTOs and CEOs, takes them out for expensive dinners and promises them the world. Then, they legacy handcuffed them forever. And virtually no one chooses to invest crazy amounts of money on migrating or even starting a new codebase when your company lifeblood has been poured into the Faustian Oracle machinery.
The ones targeted by Oracle salespeople don't. And when they do, it's too late. And most just hope things "will work out". I was third party witness to one of these transformations and I correctly predicted the chaos, uncertainty and sense of powerlessness that it would cause
And after a few years you find yourself in a situation when you already paid for Oracle so much, integrated it so deeply, so switching to any alternative is a massive pain and in most cases it’s safer and easier to keep paying Oracle.