Walmart has a "money card" that costs $3 to purchase and anytime you put money on it. You can put $500 per day on it and if you cash your paycheck, that amount can be up to $1500.
It won't count toward your credit score, but if you have no options with a traditional card, this can work.
If your question is philosophical instead of informational/practical in nature then I think the answer is that it is prohibitively inconvenient to do business, especially online, without a credit card. Of course you could pay for online things with Paypal that is connected to a bank account instead of a credit card.
I am more and more determined to boycott banks whenever possible and just pay on a cash basis, using money orders, Western Union and "money cards" when necessary. The credit reporting system is broken and highly biased, charging ridiculous and nearly insurmountable fees for those who have fallen in the pit of debt. Interest rates and penalties are unfairly high and it takes a huge amount of effort and time to recover from low credit scores.
There should be public school financial education to teach kids how to not fall into credit problems. The card companies took horrendous advantage of impressionable youths who had little to no education about credit ramifications and healthy personal financial management.
Vacationing without credit cards: perhaps Traveller's Cheques would work. I don't know much about them other than that's what they were designed for.