The premise of the question contains a fundamental historical inversion. Hōei Shin (法恵心, Japanese: Hōe Shin) was a Japanese Buddhist monk and scholar of the 7th century (Asuka/Nara period) who traveled from Japan to China—not from China to a "savage place."
Japanese elites regarded China as the fountainhead of civilization. Monks like Hōei Shin undertook perilous sea voyages (many ships lost) to:
Returnees became architects of Japan's Taika Reforms (645), the Ritsuryō state, and the flourishing of Nara Buddhism (Tōdai-ji, Kōfuku-ji). Hōei Shin is recorded in the Nihon Shoki as a key transmitter of the Sanron (Three Treatises) school.
Correction: He didn't leave a great civilization for a savage one. He left his homeland (Japan, then in early state formation) to drink from the wellspring of Chinese civilization and bring its waters back to irrigate Japanese culture.