Because business owners don't have the time and resources to keep changing vendors to save 10% costs. Time is money.

Switching cost is more than you think. For example, I don't like Zendesk it's expensive and over-engineered. But I stick to it because I know how hard it is to port my docs over and re-setup the live chat. It's half a day work. To save $50/mo, it's not worth my time. My focus is growing my company, not to save $50/mo.

I run SaaS and spent alot in SaaS products.