We the audience know that Anakin is important, but Padme doesn't. From her perspective, Anakin is just some kid she met once and then who went off with the Jedi. She's got more important things to sorry about (like the entire planet of Naboo even though she herself is barely a teenager, for some reason).

As for why the Jedi don't, I kinda like the other detailed answer but also I think they may have just screwed up because the influence of the dark side was making them make bad decisions.