There could be several reasons why English subtitles are not available on many anime sites:
1. Licensing Issues: Some anime series are licensed by streaming services or distribution companies that may restrict the availability of English subtitles on other sites to encourage viewers to watch on their platform.
2. Time and Resources: Creating subtitles is a time-consuming process that requires resources, such as translators, editors, and software. Some sites may not have the capacity to provide subtitles for all the anime they host.
3. Priority Content: Some anime sites may prioritize popular or new releases for subtitling, while older or less popular series may not receive the same attention.
4. Fan Subbing: In some cases, fansub groups provide English subtitles for anime series that are not officially licensed or subtitled. However, these groups may not cover all anime titles or may have limited capacity.
5. Region Restrictions: Some anime sites may have region restrictions that prevent certain content, including English subtitles, from being available in certain countries.
Overall, the availability of English subtitles on anime sites can vary depending on licensing agreements, resources, priorities, and other factors. It's always a good idea to check multiple sources to find the anime series you want to watch with English subtitles.