Not necessarily, if a customer has just invested a ton of money in premise based architecture or infrastructure (servers, storage, switcher/router equipment, licenses etc.) it is not likely that you are going to be able to convince them to rip that all out and move it to the cloud. That being said, they could be a great candidate for cloud services in a few short years based on the technology refresh cycle.
There could also be a situation where a customer has high sensitivity around compliance and security. The customer could have trouble getting their end users comfortable that their technology is cloud based. A hybrid approach may be better served here.
It really depends on the customer but the primary thing to focus on is staying flexible and customizing solutions that meet their requirements.