If a business cannot afford $100/year for a critical service, the business is not viable. Or to put it another way, if a forms service is not worth a large multiple of $100/year, it's not worth having a forms service.
A forms service is not just useful to businesses. I'd love to have a real contact form on my website, but it's all static and I don't really want to run the infrastructure myself. $100/year is _way_ too much for that case.
Back of napkin calculation: assuming low costs, $100/year is on the order of 1000 users per software engineer if the engineer also does support. Make it $10/year and the engineer has 10k users to support. 10x users mean 10x probabilities of long tail support events. The long tail of support is unbounded in negative consequences while the best support interaction is zero bound.
It’s not worth building a business for unprofitable customers in general. A forms service falls into the general case because a million customers is a highly unlikely. It’s also likely to require an undesirable business model. For example $10/site/year is going to be too dear for people with multiple hobby sites if $100/year is too dear.
I understand why one wouldn't necessarily target users who just need a contact form for noncommercial use. However, you could have a business product that allows for team access to forms + support that offsets the cost of the super low cost personal accounts that can't share forms or form results or use support. The actual computational resources required by personal users is likely to be minuscule, especially for something as simple as a form to email service.
> It’s not worth building a business for unprofitable customers in general.