In-verse, he's been gone for 2-4 months at best. Bringing up "10 years of writing" is completely pointless as years of writing can focus on literally just a singular day. What matters is in-verse.
Smoker's partner, Tashigi, just was part of a major event with rescuing Koby. Helmeppo just was part of a crucial event, Kujaku, Drake, Sentomaru, etc. But you believe a character who Oda's been developing since chapter 100 "Legend Begins" of the series, does not matter to the plot at all... Make that make sense.
To you Helmeppo has more plot relevance than Smoker, because he's appeared in the last 10 years of writing.....Bro what???