FsPassengers is updated often...

[pegase]

If I remember well anyway same feeling was around about Fs2004, most people
said they will never upgrade but 6 month later Fs2002 was almost dead with a few
users remaining.

Ammong the few wise traditional French tells is this one

Ne dis pas "Fontaine, je ne boirais jamais de ton eau"

never tell "fountain, I will not drink your water"

So, I don't tell that I will NEVER go to FSX. I would even tell that I WILL upgrade (Inch' Allah). But I will do it when it will offers at least as
much as I have with FS2004 with it's third party, add ons and planes and the computer fitting th requirement..
This is why I bet it will not be one day or one week after the first release but rather about one year later

About the fact you cannot promise anything today as FSX does not exits yet... it seems solid logic