Su Microsoft Downloads trovate il documento Business Planning Guide for Visual Basic 6.0 Applications che contiene informazioni "non tecniche" sul futuro delle applicazioni VB6.
Quello che faccio sempre notare a chi si "ostina" a continuare imperterrito con VB6 anche per applicazioni in continuo aggiornamento è questo:
Runtime support is in place for Windows Vista and Windows Server 2008. There is no planned runtime support beyond Windows Vista and Windows Server 2008. Windows 64-bit applications (Windows Vista and Windows Server 2008) are also supported as runtime platforms. Be aware that Visual Basic 6.0 applications execute in the WOW layer; it is not possible to mix and match 64-bit components with 32-bit components in the same process.
For third-party controls and components, support varies from vendor to vendor. As a general rule, more third-party controls are supported under Windows XP than Windows Vista; Windows Vista has many more security features than Windows XP, and some older COM components might not operate correctly, because the Windows Vista operating system has extra security around accessing and altering system resources. The WebBrowser control (TriEdit.ocx) is not supported in either Windows Vista or Windows 2008.
Prima o poi la migrazione sarà "inevitabile"... bisogna pensarci per tempo, soprattutto ora, che il supporto per l'ambiente (non per il runtime) è già scaduto da un pezzo.