Adobe is not just abandoning the mobile market; they're also picking up stakes after the next release of its PC software and leaving the desktop realm.
HTML5, which can probably be summed up as "Flash, but better," is now a universal web standard and will be filling any gaps that Adobe will be leaving. Your HTC EVO 4Gs and 3Ds already support what is to come, so there's no need to worry about the web suddenly not working one day.
We can probably expect to see Flash Player remain in the Market for quite some time; however, as new devices come out there will be no support for features that phone might offer (such as GPU 3-D rendering, or time travel).
Adobe will be working to contribute to the future of HTML5 and will continue work on Flash 11 and 12 as a 3D gaming platform/engine/multimedia plugin, so while it's not completely dead yet, it's probably time to put it on the cart.
What this might mean is we will never see a bug-free stereoscopic 3D GPU accelerated Flash Player for the HTC EVO 3D (and subsequent) platforms, but who knows. It also means there will be one less thing to update on a regular basis from the Market.[Adobe Blog]