France in the 1980s, and Spain in the 2000s opened high-speed train network. Morocco opened a high-speed train line between Tanger and Kenitra in 2018, and they're constructing it further south towards Casablanca as this question is written (2019).
This means that, theoretically it should be relatively easy and efficient to travel between western Europe and Morocco without flying planes - only the Gibraltar strait still needs to be crossed by ship and that can takes time.
However the rome2rio.com website does not suggest any easy connexion. The connexion without planes it offers between western Europe and Morocco are extremely bad and involves riding a lot of bus (no train).
Is it because rail companies are missing from their database or is there any other reason such a travel route is not possibly mostly by Train ?