All together, that would mean an efficiency of ~10^{-8}, which is about a million times smaller than for the ERL (I'm no expert there, but I think in the article they mention 1-10% efficiency).
There are prospects for much more efficient high-power lasers, but there's still a long way to go.
I don't know what would dominate the costs in this particular case, but given the low efficiency and reliability (high-power lasers break often) as well as the other issues, I wouldn't bet on wakefield accelerators as an alternative.
I think we could afford a 10^-6 wall power to EUV beam loss and still be economical probably not 10^-8... my rough estimate is that for your 100W EUV beam equivalent to what ASML provides you can afford to burn on the order of 100MW for four years and still use less dollars to pay for that power than the capital expenditure for your ASML EUV system.
If the repetition rate is too low, is it possible to re-use an electron beam and use mutliple undulators for multiple EUV beams with separate lithographic reticles? Is it the chirped-pulse-amplified lasers that have slow rep rate or is it possible to have a single driving laser with multiple plasma targets?
Is there a way it becomes viable if you can make something that is dramatically lower in cost even if it burns 10x the power?