if you think about expense wise its always miniaturisation that makes things expensive the first mobile phones were massive and stupidly expensive and hey they still are because smaller, smarter prob the same with man portable laser weapons
open up your lap top or smart phone and fix it if you have only ever done a basic at secondary school technology course, same level of complication I would think. it needs A. power pack and I don't think current lithium ion tech would cut it, B. the laser its self , gas laser, chemical laser , ect a little nugget of wikiknowledge
https://en.wikipedia.org/wiki/Laser#Types_and_operating_principles
so for argument state its a gas laser you need gas storage and how much do you need to fire off to be practical and what is the focus lense, glass ,crystal beer bottle?. C. cooling energy weapons generate heat its a principle we are all aware off so again how do you practically cool it. so yeah I think they be a strange bit of magik