My thoughts are like your's matey...except for the boat ramp bits. You'll find most are maintained by the local councils with no contribution from the State.
This was a hypothetical question.
I'll pay as long as I put the boats in the water but the question on whether or not to pay must be on the minds of a lot of people (especially those with motors less then 10hp) who once did the right thing BUT have had a gutfull of been screwed by the government...especially seeing it's rare to get court. So far there's been mention of 1 fine.
Hell, they cannot even police the lack of navigation lights at night let alone check every boat for rego.