It's precisely because you've been going with the flow of inertia that the present is what it is.
Literal
Inertia [to-に] body [object-を] entrusting-because, now-like present [subject-が] exists.
がために is a formal/emphatic variant of ために meaning 'because of,' where が reinforces the causal link. 身を任せる (entrust one's body to) is an idiom for surrendering to a situation or drifting along. 今のような現在 is slightly redundant — both mean 'now' — but emphasizes the quality of the present moment. The ~んですね ending combines explanatory force with reflective agreement-seeking.