After analysis, I think Trump, who was just advised by nuclear force commanders, has processed the expensive need to replace obsolescent systems with "building up" the force.  In fact, the number of Ohio Replacement Submarines is fewer than the number of Ohio's to be replaced, for example.  Trump talks as a layman (which he is in military matters) - or like a MSM reporter.  His terms should not be taken too literally in the precise way professionals might mean them.