If not, than one is explaining/selling again, and you will only ever have 2.7%*(time/sales_pitch_time) customers. Letting client/customers dictate the terms of a product/service often will just turn your business into a staffing agency.
B2B is actually more risk, as any deal exceeding 12% of revenue sets a timer on how long your business will likely survive. Some unlucky folks also end up acting as a product warehouse for clients, contract labor, or a scapegoat for client internal strategic mistakes.
If people can't summarize what they do in 1 sentence, than they likely have a fuzzy definition for a business project goal. For example, people that use more than 4 conditional statements (if/but/when etc.) to describe something, than I have observed they often last less than 3 years regardless of cash burn rates. =3
I broadly agree with your point, but disagree with this sentence. IME a 1-sentence business goal is almost certainly too fuzzy to be useful. There's nothing actionable about "We help you survive audits and readiness for regulation $FOO", which is frequently the business goal.