Indie hackers generally have a low/no budget.

So other indie hackers will say that a specific part of a CRM, for example, is all that would be needed, they create that SaaS and sell it for $5 per month or free (a fraction of the price of an established brand). Rinse and repeat. It's easy because indie hackers appreciate small bugs and issues and are not as demanding as someone who is paying $50 per month, working with a large corporation that needs support 24/7 etc.

It's not exclusively, but you find a lot of "indie hackers" come up with business opportunities based on following/reading/speak to other indie hackers and then market to other indie hackers and so the cycle continues

Bingo!