That is sort of true and it is mainly referring to American Express. Even they allow revolving credit on many of their cards now though so the distinction isn’t as clear as it once was. Also, ‘no limit’ doesn’t mean that the limit is truly infinite. It really means ‘no preset limit’ and that where they draw the line at any given time depends on your purchasing and payment history.
You can’t generally charge $1000 a month for years and then suddenly decide to charge something that costs $150,000 on those cards. It will be declined unless you have talked to them first and they agree.
Still, there are lots of cards with truly high limits that you can use at all will and plenty of people with charge cards and the purchasing history that can use their cards to charge something that costs in the hundreds of thousands of dollars any time they want. Lots of small business owners use company credit cards to help manage their cash flow and gain bonus rewards. They may routinely charge that much every month on a card in operating expenses and have the extremely high limit to show for it even if they aren’t personally wealthy.