What's the difference between a public pilot and a self-funded pilot?

The service period of public pilots is life, and the labor contract is 99 years. All expenses during the tuition period of public pilots are borne by airlines, but the elimination rate of public pilots is relatively high and the contract period of self-funded pilots is relatively short. Generally speaking, the cost of learning to fly is paid by yourself or guaranteed by a loan company, and the elimination rate is relatively low, but there is also a certain possibility of grounding.