Unfortunately yes. That is exactly how it works. Most Indians on H1b will never get a green card despite having an approved green card application. (the I140)
Indian wait-times are expected to be between 20-60 years. It is ~10 years of the Chinese & Mexicans. Everyone else gets a green card within 1-2 years.
What do you mean by this? Surely they don't have to stay and work 30-40yrs before they can expect permanent residency?