Your LTSpice simulation is doing exactly what you are telling it to do. By saying .TRAN 100ms, you are simulating the time history of the circuit for only about the first 6 cycles of the 60 Hz input. Since at t=0, the voltage source =0V, all of the capacitors start out with 0V across them. It takes many cycles since start-up for the circuit to reach steady state, where the capacitors have charged to their "operating" state.
To get to the steady state, you will need to lengthen the time to run the simulation by changing to .TRAN 1. Now you will see what happens over the first 60 cycles. If you don't care to see the start up, and want to see only the ripple component after the circuit reaches steady-state, then use .TRAN 1 0.83, which runs the simulation for 1s, but doesn't start plotting data until 0.83s into the run, meaning it will plot only the last few cycles...
Note that a real voltage tripler operating at 60Hz input would have a long start-up time, and lots of ripple, too. The startup time is a function of the size of the capacitors, as well as the current I1 being drawn off the output. Note that to see the ripple across the "load", you would normally plot V(n005)-V(n004). However, since there is no current flow through R1, the voltage at V(n005) is zero.
The reason I put R1 in the circuit is because all Spice variants require one node in the circuit to be defined as "ground" (GND: node 0 in the netlist). What you call "ground" is arbitrary, and I could have made n005 GND by attaching the ground symbol to it directly. The other way to do it is to add an arbitrary high-value resistor (the other end of which is GND) to one of the "floating" circuit's nodes. The current flow in this mythical resistor is zero anyway, so it has no real effect on the circuit, but it satisfies the requirement that "at least one node be GND".
In the US, one side of the 60Hz 120V AC line is at "earth ground" potential, and that is the white wire, called Neutral. Any voltage tripler powered by the 60Hz 120V AC line would likely configure the tripler so that its output is taken the way I drew it, i. e. the tripled voltage is taken with respect to Neutral, not the other line (Black or L).