[Sorry for the long message in advance]
The issue with launched coasters nowadays is that yes, although they are more efficient, they have a much greater power spike. Rita gets away with it as the launch works on pressurising nitrogen gas in accumulators to pressurise hydraulic fluid, and the pressurised hydraulic fluid is then used to effective spin a big winch really fast, to put it rather crudely. Therefore, the main energy draw is spread out over the recharge time, which is roughly the time of the countdown, as the launch doesn't pressurise until the restraints are shut, and not fully until dispatch, spreading the current draw over quite a period of time. LSM launches however, which is basically the only launch available nowadays bar compressed air, draw all their current at once. The way they work is by creating a "standing wave" inn the magnets that matches the natural fields created by the permanent magnets on the train. this "standing wave" is then accelerated along the launch, and this carries the field of the train magnets and thus the train with it (massive oversimplification) however, you have a launch that takes 2 seconds, and all the launch energy needs to go in in those 2 seconds. This is the same energy as needed for Rita (assuming same accelerated mass and final velocity) but in a fraction of the time. To demonstrate, if we say we want to launch a 8000KG train from 0-20 m/s in 2 s, (using SI units cause I can't do the conversions) then we have and acceleration of 10m/s^2 and then we can substitute into F = M x A to get 80000 N. Now we now the force on the train, we can calculate the energy draw. If we assume the launch is 20m long for the values given, then energy = force x distance, so we get 1.6 million joules. On an LSM coaster, this has to be expended in the 2 seconds of the launch, leading to a draw of 800,000W! Spreading this out over 30 seconds on a hydraulic launch gives us 53,333W, which is much better. To sum it up, even though the tech is more efficient, the power problem still exists, and even then, this launch would only reach 45 MPH, so nowhere near Rita's consumption, or that of a multi launch.