I'm afraid way too many players - many of whom are inexperienced anyway - would abuse this feature in ground events, resulting in a disastrous mess and possibly no conclusion of these. Cure ground elites were already a nightmare to complete without a good team for a time. Ground ESTFs still take skill to complete, even though they have been seriously nerfed for a while now, sometimes you don't have the privilege to run it with aces and have to resort to PUG-ing as the only option left. Also let's not forget about other ground events, many people enjoy, for example "The Big Dig", but I can see greens occasionally butting in and clogging up precious slots on teams... can't say I blame them for anything at all, it being a daily and all, but imagine how it would turn out with people running around blasting everything that gets in a 10m range and not only dying 2 seconds after, but bringing the whole squad down with them.
I'm not saying I wouldn't like the feature, just giving a thought to why it *may not* be considered to be added by the devs.
Edit: Blast, turns out you CAN enable it in the options, Thank God it's disabled by default though, don't spread the word please! I still stand by my opinion, that not everyone should use it!
From an archived post:
Ground Autofire mode is disabled by default. You have to go into Options -> Controls Tab -> Ground Region -> Auto Attack drop-down (last item at the bottom). Change it from none to whatever mode you desire. "Toggle, chance (target) cancels" is the default that Space Region uses. That is autofire will keep firing until you change targets, or select no targets. Right click on the weapon icon to enable auto-fire on that ability to make it auto fire.
auto fire does not mean auto target and kill everything!
(of course you CAN set targeting up that way too, it's an option)
auto fire means that you target your enemy be it ship or ground enemy press spacebar / 1 and start shooting at that one enemy until he dies without hammering spacebar / 1 all the time for every single shot and not having your finger free to press other more important buttons.
on ground it should be mentioned though that the firing cycle of the weapon blocks using abilities, you can queue up the next 1 ability but only the one and if a firing cycle gets in the way you may have to wait it out etc.
-> this could all be a lot smoother if the ui would not *forget* which button you queued after a second or two.