@Willy ******
while you are correct about the Extensions, Two Visa Exempt entries isn't actually correct. There used to be a limit of two within a year through Land Borders (not calendar year, but within a year, depending on when one had done previous entries), but that was removed. Visa Exempt entries through Airports has never had any limit.
Someone who uses two Visa Exempt entries and gets extensions, on their next visit may be refused at the discretion of the Immigration officer depending on previous entry history and whether the IO thinks someone is trying to live in Thailand, rather than being a genuine tourist.
Official statistics show that a genuine Thailand tourist spends 7-14 days in the country on average and doesn't maximise Exempt entries and Extensions. Those people have and most likely, will be granted multiple Visa Exempt entries within a year, especially if there's proof of returning to their home country for periods of time. As you said, two Exempt entries and those extensions, are still generous.