each of those have a pretty prominent 'contact sales' link on the landing pages and pricing pages, so I have to heavily disagree, they all employ a sales forces.
For certain apps it might seem like they sell themselves for small users or individuals, but as soon as the customer is 'enterprise' the route is virtually always 'contact sales' like on Stripe and Webflow's landing page, on shopify's pricing page the larger tiers are also 'contact sales'.
There's still a difference between having an account manager at a company, in charge of implementation and support, and an active sales force that goes out of its way to sell stuff, lie to prospects, wine and dine them, etc. Stripe, Webflow, Shopify, etc. have the former - they don't really have to sell themselves.
Enterprise needs a different "sales" channel, because most enterprises are bulky, cumbersome sloths who need handholding. At the same time, there isn't anything in particular that's stopping enterprise users from using these products on a lower tier - I've used Zapier before with blessing and no issues, on the company card, at my old job at a megafund (where we had strict restrictions on a lot of software otherwise). No questions asked.
For certain apps it might seem like they sell themselves for small users or individuals, but as soon as the customer is 'enterprise' the route is virtually always 'contact sales' like on Stripe and Webflow's landing page, on shopify's pricing page the larger tiers are also 'contact sales'.