>>8823298There are a few newer Qman/Enlighten submarine sets too.
Their "Kyanite Squad" range is about mining crystals. Some sets are submarines, and mining robots. Their style is more towards the newer Lego City submarines, but they might work with the Aquanauts.
Pic related for example. The sets are not bad at all.
I like those "compatible" sets towards existing Lego ranges without directly copying something.
They really should do this with some of the most iconic old ranges, but as you said, i doubt they think that there is much money to be made.