This is an economically invalid argument without more detail. The only way a lithography process can be too expensive is if it has an extremely skewed lag time (i.e. 6 months prep per line, with low throughput) or if the consumables of the process are very expensive or very wasted.
None of the possible future processes has any of these constraints (with the exception of perhaps E-beam lithography, but it's not a hard constraint).
If you can build a continuous fabrication line with a process, then no matter how much it costs, the capital-investment eventually diminishes to a tiny fraction of the cost of each chip, compared to consumables.
Current lithography processes were "too expensive" previously. But they've been running continuously since they were built, and so are again a tiny fraction of the cost of an actual processor today.
Another factor to consider is discounting. Even if a technology has zero marginal cost, it's not necessarily profitable when you take opportunity cost and discounting into account.
None of the possible future processes has any of these constraints (with the exception of perhaps E-beam lithography, but it's not a hard constraint).
If you can build a continuous fabrication line with a process, then no matter how much it costs, the capital-investment eventually diminishes to a tiny fraction of the cost of each chip, compared to consumables.
Current lithography processes were "too expensive" previously. But they've been running continuously since they were built, and so are again a tiny fraction of the cost of an actual processor today.