As jimbuna, mookiemookie and McBeck point out, it's simple economics.
With (obviously) a lot of personal enthusiasm and commitment by the dev team thrown in. Not to mention the selfless, unpaid efforts of the extensive modder community.
I don't like the unfinished parts either. Had to re-enable the dumb 2-D pop-up radio control from SH3 to get live music back in the boat. It would have been much nicer to go below to the radio room, click on that big antique box, see the rainbow dial slowly glow to life and watch the needle move across the arc as I scan for channels. Want more things like this finished? Then stop belly-aching and instead talk a few friends into buying SH5 too. With double the sales volume, it is a sure bet that we will get a better, more finished effort in future.
The negativity and "loathing" should instead be entirely focused on the lowlife thieves, most of whom come here to this forum ("Hey, why can't I see the mission objectives marked on my map?") expecting to not only shaft the economic equation that keeps SH afloat but to sponge off the efforts of the paying community here that is ultimately responsible for SH's existence and success.
