Of infantry classes, there is 2 of 5, that can reliably engage vehicles with an actual weapon at a distance. The 3rd, is an Engineer with stationary Turrets, Land-mines that must be deployed in advance or onto the target, or the ineffective-against-vehicles Archer Anti-material Rifle. The remaining Medic, has C-4 if that, which has a melee-range to deploy, and costs nanites; Unlike everything but Land mines listed above. And finally Infiltrator, has no anti-vehicle options beyond the "Explosive Bolts" Crossbow, if it carrying it. Which basically puts a "Kill me now" sign over the infiltrator's head more often than actually helps. So onto the 2 classes that can engage vehicles reliably: Heavy Assault with the Rocket Launcher, and Light Assault with the Rocklet Rifle. Of the two, the Rocket Launcher has more range but fires one shot in most cases, with it being outpaced by repair tools. The second, Rocklet Rifle, has incredible drop, and is classified as a Finisher of on-fire vehicles not a vehicle killer. Both weapons have a longer-reload, a shorter-range, and need nearly the entire supply of ammunition per weapon to land on target to destroy it, assuming it doesn't repair, nor has allies, nor manages to land a single hit on said infantry. So that's incredibly not in favor of those infantry classes, actually able to Engage the targets reliably. The Engineer is mostly defensive with their tools, and requires the most exposure time for the Turret. Which is often called a Death trap. So to contest the vehicle's presence, is to basically have less than 50% odds to win the combat for the brief moment. Or evade it instead, and that assumes the infantry even has weapons capable of being used. AA Launchers for Example, can not be dumb-fired onto, nor lock onto the Tank. Rocklet Rifle requires the ability to reach the target; Generally while completely exposed. C-4 requires Melee range, and has a time requirement after landing the brick, to then detonate. Crossbow is a joke at AV, when facing most vehicles let alone a Bloody tank. (Which is logical) Now against other infantry, every class has at least 50% or better to win a fight against singular or multiple infantry. And is more likely to be able to fire-back in nearly all instances. Unlike against vehicles. Not always can you defend with Infantry & Vehicles "properly" due to lack of nanites, lack of people, or due to Enemy aircraft giving your side the middle finger. As well, even if you pull vehicles at the next base over: What changed to allow you to win that vehicle fight? As if you lost it the first time, and now with having infantry defend the points in said base, why can you win it now? Unless the enemy's infantry was such a deciding factor, you can't unless something changed. And even then, this requires the enemy's infantry to be near solely inside competing with your sides. Which means You have less of a force, which makes it illogical to bloody win now if you lost previously. A lot of bases, have this issue where the distance is small. Or the whole bit about the enemy wining the exterior combat the first time. In order for a different result, something else must change. Just since the Enemy is or isn't firing, doesn't mean you can be a proper threat to them. If that Sniper is quite literally requiring the most work, requires specific classes (actual snipers do not), has the range advantage, armor advantage, needs one body-shot compared to your 5-10 shot salvo, Your odds of victory are incredibly low to begin with. For most people, that's basically a worthless venture, as it gives certs to the target and zero to the people being destroyed. As unless they have multiple people, willing to gamble over getting any EXP for their efforts, and able to respond to it, it's basically suicide if they couldn't solo the enemy vehicle by themselves already. Not to mention, the vehicle easily can have Radar, see behind it, has two guns independently operated, and has the armor advantage. Comparing that kind of hard target with low odds making it a 10/90 gamble, to choosing a 50-50 gamble seems more profitable. Let alone the time component of killing the tank, in addition to the risk factor. Also, the vehicles can easily keep coming, and fire at a long distance. They aren't even guaranteed to be able to be hit. Infantry inside the base? You have better odds, have the same range on average, reinforcements, same health, same armor, smaller risk factor as well. It's not like infantry are passing up winning the lotto by not engaging vehicles. Nor are they missing a wondrous brilliance of Changing the result of the battle if they do the same thing that resulted in a loss. Aka If the enemy won the first time, they will win it again, unless something changed to allow it to be different. If I press a button that grants a fixed 50 points. I can not get 100 points from the same button, unless the fixed value of that Button changed before pressing it.