Lanefan
Victoria Rules
Depends. If six months work gets you ten-fifteen years of play, it seems a decent tradeoff.See, that's why I mentioned the alternative.
Me? I'd play 6 months of something like Ironsworn (maybe modify it a bit to make it more D&D fantasty, say). Which means my setting is ready for play in about 20 minutes. I then spend the next six months collaboratively building a detailed, intricate setting with my players, in play, that will result in a compete, living setting that everyone at the table is directly linked into.
Which I can then use to build other campaigns if I so choose.
If D&D (or any RPG for that matter) requires SIX MONTHS of work before it's playable, then RPG'S are dead.
Ignoring things like vacation trips, I've been DMing pretty much weekly or twice-weekly since 1984, with three gaps:
1994-95 10 months between finishing one campaign and (somewhat unexpectedly, I got talked into it) starting another
1997-98 1.5 years during which I ran maybe 4 sessions (only had 2 players and they didn't want to run without a third; the game I was playing in at the time also nearly died, same reason)
2007-08 9 months between campaigns, during which I ran a 3-session one-off as a playtest while designing what's now my homebrew setting
During all three of those gaps I was active as a player. But some downtime from DMing can be a nice break, too.
That, and keep in mind the prep for the new campaign or setting can happen while the old one is still winding down, if one has that degree of foresight.