You have obviously missed something here.... None of the people on this mailing list are paid to sit and breathlessly await mailing list messages and respond to them within seconds. This means that sending multiple insistent requests to the lists within a few minutes just pisses people off, and is reasonably likely to get you banned from the list rather than a friendly response - even more so when you do this on a day that is a national holiday across rather a wide part of the world (notwithstanding cancellations of holidays in much of the world at present due to major disasters).
Are mailing lists reliable....? Well what do you mean by reliable? Will you get accurate precise answers to questions from them? Well sometimes, other times you get garbage, and you should always believe anything you read on the Internet. Will they reliably deliver mail? Yes, with caveats (if someone has a broken mail system then the mail will get lost there from lists as well as from other sources).
Nigel.