Licensing limbo is the main reason. Rights to the film have changed hands multiple times (Toho, Miramax, Echo Bridge, and currently Janus Films/Criterion). The Omni dub hasn’t been reissued on official DVD or Blu-ray since the early 2000s. Modern releases (like Criterion’s 2019 Godzilla: The Showa-Era box set don’t include it—that set stops at 1975, and Criterion’s 2022 4K of Biollante used the original Japanese audio with subtitles, not the Omni dub).
Full dubs circulate on YouTube, Internet Archive, and fan sites, but these are unauthorized uploads. They’re often poor quality (VHS rips with tracking lines) and can disappear due to copyright claims. I can’t provide links, but you’re free to search using terms like “ Godzilla vs Biollante English dub archive ” at your own discretion. godzilla vs biollante english dub full movie
Unlike later Heisei-era Godzilla films (1991–1995) that received consistent English dubs from Sony, Biollante was dubbed in 1992 by a small company called Omni Productions (famous for their energetic, sometimes loose translations of Hong Kong and Japanese films). This dub aired sporadically on U.S. TV (like the Sci-Fi Channel) and appeared on a rare 1998 VHS from HBO Video. Licensing limbo is the main reason