It’s a tough trade-off overall… I do agree that time passes too quickly, and that the flow of the game would benefit greatly from vehicles being able to make a more significant number of round-trips inside each year.
The problem is, I’ve already sunk 50 hours into this game, and I’m only half-way through my first full play, having sunk maybe 30 hours into this map alone!
For that reason, I think slowing the passage of time, and accordingly adjusting income levels and such to maintain the ecomonic balance, can only really be feasible if it’s possible to add faster time-multipliers to the game speed. If the game was slowed down by a factor of 4, we’d really need a 16x speedup button.
Otherwise, with a factor of 4 slowdown, it would take 60 hours minimum to get through 200 years, even if you ran the entire game at 4x speedup!