We all know how voyages work. Buy one from a trading company of choice, propose it on the voyage/captain's table, vote on it and bam, voyage. As a maxed out Pirate Legend, most of the voyages I can purchase cost around or above 250 gold. Selling a seafarer's chest will return the amount of money I spent on a voyage really easily.
Why do I mention this? Sea of Thieves allows its users to be able to pick things up and put them down like a toddler in day care, there's nothing wrong with this design ideally. You either do a voyage or you don't; you finish a fort or you don't; you finish a tall tale or you don't (and have a checkpoint for reduced headaches in the future). The issue comes down to commitment and the worth of a proposed voyage.
A lv 50+ Gold Hoarder voyage will get you far more gold than you spent purchasing the quest by an extremely large sum over 4 times it's amount. If I was getting hounded by an enemy ship and felt like not committing to the voyage during my session, I can just... not do it, there's no punishment to tackling a voyage and refusing to complete it other than missing out on a very measly sum of gold, not just in voyage cost, but in voyage profits as well.
Voyages are not worth anything on the Sea of Thieves, and any player paranoid, bored, or short for time can just vote to cancel a voyage (assuming the crew has immediate access to their vessel) or "Leave Game" at any point. This makes it particularly difficult for tougher pirates to successfully steal loot from another crew's voyage, most infamously, with the base Athena's Fortune voyage and it's ashen counterpart. A player in imminent danger can just log off before finishing the voyage or even getting to the dig up of the coveted Chest of Legends. Before Fort of the Damned and Fort of Fortune, Legendary Thief was a title that had a true rite of passage due to the insane difficulty of stealing a Chest of Legends through sneak plays or well executed ambushes.
Where is my point with all of this? Simple. Voyages are worth nothing and don't punish the voyage owner for unsuccessfully completing the voyage and selling the loot from said voyage. Being down 250 gold is merely pocket change in comparison to tougher pirates who happily spend over 20k gold having barely enough supplies to steal a world event from an over-prepared Grade V Reaper. Why have the prices of the voyages always stayed this low? This allows for players to easily purchase voyages when they have nothing better to do... except that's exactly what the Messages in a Bottle/Tattered Parchements are meant to do.
Voyages need to have worth in them similar to the supplies and commodities you can buy from the Merchant Alliance. This way, pirates need to make the conscious decision to do a certain type of voyage as if they do not fulfill it, they will lose a meaningful amount of gold doing so, and on top of that, make fights, encounters, and decisions much more meaningful to the pirate to help influence the story. "Should these rusty sea dogs refuse to commit to digging up a Chest of Legends at the cost of the 15k gold they spent for the voyage because they're being chased by tougher than average pirates? Maybe they will fight for the loot they dared to put on board to make at least double of what they spent, maybe they will cower and evade combat for as long as they can, or until they ultimately surrender their worth to the Devil's Shroud, or their predating chaser."
Players genuinely don't care about voyages enough, and I feel that giving them a price to not only work for, but to also risk will make voyages (regardless of their fun factor) much more of a conscious decision to perform, at least for Pirate Legends, seeing that there was expectation for Veterans to have over 77 million gold after potentially 3 years or less of overall participation time. Surely they have a lot more gold to spend, so make 'em spend it on a voyage they want to do, as it worked relatively well for Athena's Run of Thieves' Haven, as Doubloons are tougher to come by.
