Something to consider is that using a non-industrial laser to do this (something smaller than a huge gantry 1500 x 3000 or more) is that you will still be cutting the fabric out to fit the bed of your laser.
This takes up a lot of material and cuts rather drastically into the time ‘saved’ by the laser.
Have you done much sewing of garments on an industrial scale before? There’s a lot that goes into making it an economically-viable enterprise. There’s a reason most of our clothing is made by what basically constitutes slave labour…
I am a big-time clothing-maker. I learned it first when I was still learning to read. I used to do it industrially, and I’ve done it for the theatre, and I still do it for myself, what I’m getting at is that I’m really very experienced in this field, and the laser one, and there are very very good reasons why I don’t reach for the laser when it comes to cutting out pieces.
Even on a laser with a huge bed that would reduce the need to cut the fabric into wasteful pieces, you can’t stack the fabric up like you would in a traditional production environment (fabrics and papers catch fire in a laser if you try to cut a stack), meaning that you’re really not saving any time, because you have to cut each layer 1-by-1 and then also take all those pieces off the table and sort and categorise them for sewing.
Wheres with the saw I mentioned earlier, you will have a stack of 20 layers or so, each with a piece of paper on top stating what part and size it is, ready to be passed to the sewers.
Plus lasers either burn the edges away (on natural fibers) which then, when rubbed around make the fresh pieces all sooty and gross, or they melt the edges (synthetic ones), which are crispy and awful against the skin.
Also because of the high surface area of these materials, they’re very prone to catching fire, even moreso than cardboard.
And because it’s hard to secure the pieces after cutting, they get whisked into the exhaust fans. You can add tabs to keep them attached to the waste fabric, but then you have to manually trim them after.
If you just wanted to do some one-off home-sewing things that needed to be accurate or would be fiddly by hand (I’m thinking use-cases like cosplay perhaps) I can see lasers being somewhat useful, but I couldn’t recommend them on an industrial scale.
I adore lasers, but they aren’t the tool for every job. 
I would recommend looking into some huge tables, the type of saw used for clothing production and maybe a roll-fed plotter for printing out your patterns, so you can just lay that on top of your stack of fabric, and get cutting.