True, though it also requires a belief that the company will honor the contract (and be able to), which is hard to rely on too much with many startups. Due to the desire not to complicate potential exits, startups also tend to be wary of signing service-guarantee contracts that can persist through acquisition; just about any service contract I've seen from a startup includes clauses about it going poof if the company is acquired.
Could be an angle for big companies like IBM and Microsoft's cloud offerings, or at least that's what they're trying to push, with pitches of: come get something reliable from us, with guaranteed service that we'll actually honor and will still honor in 10 years, instead of some startup that might be dead or bought next year.
