The ISO 9001 is a sham, and a scam moneymaker for the ISO testing industry.

Just because other firms haven't got ISO9001 doesn't mean they could not get it, it means they haven't bothered wasting money and time on it.
I know firms who got it for example, for their marketing dept, not for their product, and then proudly displayed the ISO9001 logo on everything as if it was their product that had achieved it. It was purely for selling purposes to customers who didn't understand that it wasn't for the product, it was for the marketing dept who was currently mis-selling to them!

I once had the project to get ISO 9001 for my employer. It was a balls-ache of bureaucracy and didn't measure the quality of the product but the quality of how we went about it. It was an endless paper trail and guess what it measured - our paper forms! In effect we had to write and keep an exact history of every type of form and every change to every form, it was ludicrous beyond words.
The 9001 system was - set a standard, measure it, hold review meetings to move to the standard you have set, measure, review, measure, review........... The consultants hired by my employer to help at great cost (see what I mean about it being a scam for the testing industry) eventually agreed with me that if I set a standard of taking 2 minutes to answer the phone, be rude to customer on phone, measured how our staff did against that standard and rebuked anyone who answered the phone quickly and politely, I would have complied with the rules of ISO9001. But they wouldn't award us ISO9001 because that would be against the spirit of it. To which I pointed out that they couldn't refuse since I would be complying with the rules and secondly what if I chose some obscure technical thing they didn't understand at all but in effect did the same bad process then not only would I have complied but they wouldn't understand it was a "bad" thing and would happily award ISO9001.

Then the consultants pointed out that ISO9001 examiners were beginning to regard the "Investors in People" award as necessary to pass the ISO9001, and guess what, they could help us with that for a huge fat fee so that we could put "Investors in People" logo on staff redundancy letters. The consultants and examiners were working a fraud by deciding that they wouldn't give ISO without "Investors in People" as well, thus guaranteeing even more fees for themselves.

It's a rotten industry and I have less trust in an ISO9001 firm than I do with one that doesn't have it.