I (=as the employee of the company) often don't want to bother to pay, because a business case, then getting the invoice right (if that is even possible and the seller allows paying by PO), then getting it paid in time, is often not worth it. Often free alternatives exist, which makes it even more a no-brainer. Never mind that as a whole we are an enormous company but software dev is not core business so really we are a small part of a whole, yet some sellers only want to sell the most expensive enterprise tier.