I'm not sure if it is really impossible, but there are some tough nuts to crack:
- Most current devices don't have the display resolution to run Lazarus. Retina upped the ante on the iOS side, and some Android vendors are following that example (e.g. Yarvik Noble and some Yenta versions), so that might be ok in time.
- (heavy) compilation is a battery drainer.
- Processors are also coming along nicely, but the fastest ARMs are still only in the Atom ranges. You don't want a recompile of Lazarus to install a component to last an hour on a battery. SSD Flash is fast, but most SD cards are actually slower than HDDs for read/write operation
- how to operate the GUI?
- How much access does an app actually have to the underlying OS? Can it actually fire other apps (like make and FPC) ? Are threads supported? Might need a rooted android.
- Does android devices have some way to install the required toolchain bits (make, as,ar,ld among others)? Yes FPC supports Linux, but might require more Linux than android standardly provides.
So while Android is probably not impossible, I think it will only run on PC like android devices, probably development boards, plugged in, with some fast storage device (SSD or HDD), a high res screen (probably a normal monitor) and normal keyboard and mouse.
Anything else needs to crack some nuts first, and do it in a way that doesn't detract from mainline Lazarus development. (so no changing lazarus to do touch everywhere).
And even for the easier development board scenario, somebody has to step up and do the work. Preferably owning a suitable device. You?