There can be various Pratyekbuddha who would have attained “Enlightenment” but would have not bothered to teach others.
These Pratyekbuddha would have not taken efforts to create Sanghas or Communes. Having said this,
the achievement of Pratyekbuddha is no less than Sammasambuddha. The only difference is their intent to teach or not to teach.
To understand the difference between Pratyekbuddha and Sammasambuddha, let us take the example of Abraham. When Ismael was born to Abraham, he symbolically attained a particular milestone in enlightenment. When Isaac was born to Abraham, he again attained the ultimate milestone in enlightenment. God asked him to sacrifice both his sons. However angels prevented him to do so.
Miteiya suggests a great connection between Buddhism and Ismael. He also connects Isaac with the future Buddha. Had Ismael and Isaac been sacrificed, the legend of Abraham would have remained as a “Pratyekbuddha”. But since the achievements like Isaac and Ismael were left alive to help the mankind, the legend of Abraham becomes a Sammasambuddha. A Sammasambuddha is none but a patriarch or a prophet.
For a person who has become Pratyekbuddha, it is a big sacrifice and botheration to take the responsibility of teaching. Having been liberated, one would not like to bind him or her into any further responsibility. However there are few people who commence teachings to honor the instructions of God. Such people should hence be respected and not looked upon with doubts.