How is the decision made to produce a vinyl record on different

It astounds me me that an "audiophile" LP and SACD label owner who has invested as much as has Chad Kassem (who started in business buying and selling original pressings of rare and/or out-of-print LP's) in advancing the state-of-the-art in LP production has his motives and integrity called into question by nobodies. Chad has single-handedly done more for the LP since anyone from back in the 1950's. If you don't know that, you (as the hillbilly said to Ned Beatty's character in Deliverance) don't know nuthin'.   

I think the marketing theory is correct. I have some really marginal 200gram pressings. Most are great… some very disappointing.

Marketing department generates ad copy. Production looks at ad copy sets pressing accordingly. I know what you're thinking. 45, one-side blank, remaster (digital or otherwise), same thing. 

Both Michael Hobson (Classic Records) and Chad Kassem (Analogue Productions) discovered that 200 grams is too much PVC for the presses, 180 grams a good maximum figure. The only scientific way to ascertain the benefits vs. liabilities of different weight LP's is to take the source tape and produced different weight records, then compare them by listening. As far as I know, no one has yet done that. That would be a great question to ask of Kassem.

I suspect mainly marketing.  Put it on 180 and suddenly it's "audiophile quality"  While some formulations are definitely quieter I've never heard a correlation between vinyl weight and SQ in my system.