One could argue that existing software even if legacy works and gets the job done so what is to (significantly) gain from writing new (and improved) software?
Most positions I've seen do not look like they pay that well. You can make more as a processor in a shop on land and work a regular 8-5 job. On the boats you get a 12-hour tour for the duration and the only real perk that might make it worthwhile is the opportunity to visit foreign ports and dawdle during breaks.
Survey automation is a complex task because depending on whether you are a marine crew or a land crew. Some things are easier in marine work due to less cultural constraints (buildings, highways, pipelines, etc.) But in the same way it is easier on land to locate and replace any sensor that fails without losing much data from that receiver location. For best imaging you need to be able to avoid introducing holes in your data coverage and correct anything that causes a data loss. Redundancy is a real thing out there.
The industry has morphed into one where many larger acquisition contractors have divested themselves of the ships needed to acquire the surveys and they contract that now to custom acquisition crews. Everything went bare-bones a rawhides in the last downturn and as we know, seismic exploration is one of the last things to recover after a bust.
Also, there is a shift in the industry from ownership of the survey equipment (sensors, recording systems, etc.) to rental of everything. Manufacturers build it all, rent it out for custom surveys, maintain it and service it all, train the equipment operators, etc. That cuts costs and makes acquisition a matter of retaining trained personnel for key positions and recruiting trainable people for the rest.
I've also seen a lot of geo/petro phsycists/processors intentionally not want to help because they know heavy automation endangers their job.