That's not true.
If cold-calling doesn't scale it's usually the underlying business that's not going to scale, not the method of marketing.
Marc Benioff (Salesforce CEO) built his company around "inside sales" which is essentially cold-calling with a fancy wrapping.
A recipe to scale cold calling for an entrepreneur is:
a) Get very specific about who your customer is, and how you're finding them. For instance if you're selling small business websites to dentists maybe that's "go type in "dentists" on Google, and see who's advertising, and then click through and hit the "contact" button".
b) At scale you can then pay somebody else to do the work for you, large list brokers like InfoUSA have millions of consumer and business records for you to reach out to.
c) Get caffeinated, find your courage, and pick up the phone to start placing phone calls.
d) Based on your interactions build yourself a script (or at very least bullet points) that gives you an outline of how to contact the customer including FAQ that you encounter.
e) Build with the end in mind of bringing in your first "inside sales" person. You want to literally turn over a handbook of how you're working this process. Throw out a juicy commission on orders, and then rinse and repeat.
This takes work, but it's an extremely efficient way of building your business particularly for B2B.