Its been said by people smarter than I, that lasers are a lot like blast-furnaces that happen to release a bit of coherent light. Well, maybe not smarter, but holding engineering degrees at least. But they're probably right about why we haven't used lasers much over the last eighty years as something other than a guidance system. Its like a formula one car - its not all that fuel efficient, and you can't use it on real roads - so why?
Well, because they're good against missiles for one. Missiles became really common on the battlefield - a drone you can barely see can carry a supersonic missile, so you've got all of four seconds to react to a something you can't hear until after its passed. Worse yet, they don't even hit the tank - they explode several meters away and create kinetic-kill explosively formed projectiles to do the hard work. Leaving radar running will probably give away your position, so these systems tend to detect weapons using a combination of LIDAR or sonar (backed by radar once they have a fix on you and stealth doesn't matter, of course).
These hard kill systems tend to be more limited by coolant than than anything else - the emitters heat up rapidly. They also burn some sort of fuel to rapidly produce energy, so they are ammunition limited, but can go for quite some time. In theory, you could make a man portable version, but it would be more akin to a world war two flame thrower than a ray gun.
At least that might work. Things like ions or plasma would rapidly fail due to atmospheric resistance or blooming as a compact but hot ball of gas obeyed the laws of physics. Remember that stuff they teach you in school about how alpha particles only go a few feet in air and are stopped by a sheet of paper and beta radiation is stopped by aluminum foil? Well, since your sci-fi ion cannon is basically a beta-ray gun, well, as the evil overlord rule-book says - if an eight-year-old can explain why your super-weapon doesn't work, try something else.
Why the aliens have lasers, I don't know. Different laboratories, different funding I guess. People have reported seeing white smoke or steam coming from the giant lotus towers after firing, so I'm guessing they have some sort of open-cycle cooling, at least after a major engagement. Those radiation guns are either big X-ray tubes, or lasers on a much smaller wave-length than most. They still use projectiles for personal weapons, so the tech isn't that miniaturized though - just small enough for a 15 foot tall robot suit or a thirty foot tall tower. Are they even that tall - we don't know if they extend underground really.
Yeah, there are some people who are disappointed by our lack of magical ray-guns and flying cars, when they aren't complaining about the actual miracles like arcology mega-structures and nano-vac. However you can shut them up by pointing out we did manage to build a few lasers worthy of a James Bond villain - they're just stuck permanently pointing upwards. For satellites, rather than a rocket, we use a big rail cannon to get the thing into the sky, and then a huge laser to vaporize a fuel element underneath to provide extra thrust - no more big, dumb rockets, and thus a lot less space junk. Actually, the space lasers can be used to ablate the space junk and help bring it down - "laser brooms" as the magazine article called them.