All sūtras preached prior to the Lotus Sūtra state that bodhisattvas and ordinary people are able to attain Buddhahood, but never the people of the Two Vehicles. Thinking that they can become Buddhas while the people of the Two Vehicles cannot, wise bodhisattvas and ignorant people throughout the six realms felt happy. The people of the Two Vehicles plunged into grief and thought, “We should not have entered the Buddhist way.” Now in the Lotus Sūtra, they are guaranteed of attaining Buddhahood, so not only the people of the Two Vehicles, but also the people of the nine realms will all become Buddhas. Upon hearing this dharma, bodhisattvas realized their misunderstanding. As stated in the pre-Lotus sūtras, if the people of the Two Vehicles cannot attain Buddhahood, then the Four Great Vows cannot be accomplished. Consequently, bodhisattvas would also be unable to become Buddhas. When it was preached that people of the Two Vehicles were unable to attain Buddhahood, they should not have been left alone in sadness; bodhisattvas should have joined them in grief.

Shōjō Daijō Fumbetsu-shō, The Differences between Hinayana and Mahayana Teachings, Writings of Nichiren Shōnin, Doctrine 2, Page 194-195.

Having never studied other forms of Buddhism I’m always puzzled how followers of pre-Lotus sūtras even approach the Bodhisattva vows knowing that some sentient beings are excluded. What does “Sentient beings are innumerable; I vow to save them all” mean if Śrāvakas and Pratyekabuddhas are excluded?