Formula being pushed onto pediatrician's by pharmaceutical companies??

I feel as if formulas are sometimes pushed onto doctors to push onto mothers to give their babies b/c my son has been on about 4 diff formulas & he's 7 weeks old. I put him on the Similac for breastfeeding Mom's who want to introduce formula to their babies from Gerber Good Start b/c my son was gassy & then he wasn't gaining weight so they put him on Enfamil (which I like the best) for premies just to gain weight even tho he's not a premie. He was 8, 4 at birth lol.. then it was Enfamil Prosobee, soy formula for the gas & I liked it for the most part. The new pediatrician has him on Similac Alimentum for food allergies & colic again, due to the gas, but this formula happens to be the most expensive on the shelf & $$ ain't the issue at all but I had to reschedule my appt & thank God I did b/c 4 days after being on this 1, he started getting really bad gas again!!!! So it wouldn't have been enough time to tell amyway..

I'm just wondering, what do you guys think? I def don't think all pediatritian's do this but I have to wonder about this new one, it's also the 1st 1 he's seen. He went to the Newborn Clinic at 1st & I felt they were genuinely trying to help & giving me enough formula to try until coming back. This pediatrician gave me a 2 day supply & my son wasn't being seen for 4 days again. So I had to go buy the smallest can of formula they sell for almost $30..!! I don't mind but I thought that was shotty since insurance covers it all!

Sorry to ramble but our kids are our lives... what do you guys honestly think???