As a small company, you don't want to deal with small companies because it's too much effort. You just want to deal with one huge company which is your supplier for all your services. But you do want your clients to come to you and negotiate with your small company.
Assume your clients have the same mindset as you: why would they buy from you instead of buying from the same "one-stop-shop" where you're buying everything? They don't want to deal with small businesses such as yours, just like you don't want to.
Your "supplier of all services" might not offer what you're offering right now, but the day they do, you'll quickly be out of business. You and, gradually, all other businesses.
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As a tangential note: 50 IT service providers is a darn lot. I suspect that is 10x of what the average business needs.