If you don't believe this is an issue, here, read about how Francesca Albanese, despite being an Italian citizen living in Europe, can't own credit cards or open bank accounts, a punishment imposed on her by the US for reporting the Gaza genocide for the UN.

I did ask. Specifically I asked what you were talking about. All you really had to say was Visa and MasterCard are USA companies that handle card transactions. If you had clarified that initially you wouldn't be getting downvoted to hell.

you should ask, not assume others are in the wrong.

You also shouldn't assume that, maybe if you think others don't understand something, it's actually because you're wrong

How is a deposit not practical? Unless they require it in cash that has to then at the end be picked up at the pickup point (which would be crazy)? A rental company is taking a huge risk by renting cars to any random person with a driving license. It's the same reason they don't typically rent to people below 25 (or without a higher deposit).

It's really only unpractical if you don't have enough money on your account to afford the deposit, but then why are you renting cars? Otherwise you just pay a bit more the first time and then get that money deposited back on your account when you return the car. There's basically no difference in the end other than a bigger number the first time, and if you wreck the car or something, you will lose the deposit through your credit card too.

Being traveling tech is absolutely not usual occupancy, so it doesn't change what I said. But if you work in Europe and traveling around, and moving around instruments is part of your job, you should have a company card anyway for it, so again, it doesn't really matter for the rest of Europeans.
What I'm trying to convey, that even though you will have some incompetence without American run banking systems, unless you're in a very specific operation, like needing to rent a car at an airport for example, you wouldn't be severely inconvenient.
I'm saying it as a refugee from a country that (for justifiable reasons) is getting some negativity around, and being born there I'm deemed not actually a good person in advance, and it took me a lot of time to convince various governments that I'm not a dangerous exemplar of my race. The time I spent without access to international banking systems like Visa weren't debilitating, even though inconvenient at times.

Also, you are just wrong about the big names you mentioned:

You never said your statement was just about airport car rentals. Over here that is very likely not the most common usage of rentals (and certainly if you exclude business travel and holidays), since airports are far between, but car rentals are all over the place, far away from those airports. You rent cars over here if you dont own a car and need transportation. Or if you have to move a large amount of items you rent a van.

Besides, you can simply take the bus or train from any airport to a real car rental which should be close by in any major city. Of course if you go do it in a business hub you will find scams for the average person. Does that sacrifice a little bit of convenience, sure. But if you buy all your water from street vendors at a tourist attraction we dont claim water is expensive.

I can see you are simply from a very different world, that of business travel, which is why your perspective is so different.

EDIT: And no, I didn't use a mom and pop shop, I used the biggest car renter in my country (Netherlands) with over 130 locations.