Reasons Forge isn't coming to Bedrock:
Bedrock is written in C++, which is much harder to decompile than Java
Bedrock runs on Xbox 1, PS4, and Switch. Inserting Forge's code onto a console is even harder (Console makers hate homebrew)
Furthermore, the decompiled code is nearly impossible to make sense of (or deobfuscate) so modders won't know what they're doing
Well there you go. Unless Mojang makes Minecraft open-source, Bedrock modding is very, very, very, very hard to do.