30 years of incompetence
Dragon Warrior I - had to have it's name changed because of licensing issues, gave the game away for free, still considered a success
Dragon Warrior II - extremely difficult, no significant changes from JP version to make it any easier, admittedly one of the worst DQ games especially for DQ beginners and children
Dragon Warrior III - zero marketing, released well into SNES lifespan
Dragon Warrior IV - zero marketing, released well into SNES lifespan
Dragon Quest I, II & III SNES - would've been a great time to reintroduce the series to western fans with the QOL improvements, but nope, didn't bother
Dragon Quest V & VI - didn't even bother releasing them
Dragon Warrior VII - released after PS2 was already out, zero marketing, admittedly looks like dogshit graphically
Dragon Quest VIII - they actually gave the game the time and attention is deserves, proper marketing, drummed up a good amount of hype for it, and what do you know? It sold really well.
Dragon Quest IX - how did S-E capitalize on DQ8's success? By dumping the publishing on Nintendo and telling them to handle it. DQIX still ended up being successful in the west, but S-E didn't want anything to do with it for whatever reason.
Dragon Quest IV, V & VI remakes - zero marketing, changed all the names up, took out the party chat in IV because they were too lazy to localize the text, didn't even bother publishing VI and dumped it on Nintendo again, etc.
Dragon Quest X - nope
Dragon Quest VII 3DS - released 3 1/2 YEARS LATER DEAR GOD
Dragon Quest Builders, Heroes I & II - here's a great idea, let's completely ignore the series in the west for 7 years, not even bother localizing the mainline entry, then release a bunch of spinoffs with zero marketing and hope they sell well
Dragon Quest XI - please don't fuck this up