I wouldn't mind it, so long as the tax is laid out in advance and properly authorized. A sudden, spontaneous "tax" levied only because the PCs have very suddenly become wealthy, and which is only levied on the PCs....that would be another story. But you resist illegitimate authority by proving yourself more legitimate, not by behaving in illegitimate ways yourself.
I think it would be more accurate to say that you have been trying to run a game of that type, while using the tools designed for the other type, and thus feeling frustrated by the failure of the tools to achieve the desired end. I can say that my campaign has been pretty fulfilling for my players, and I have played in a pretty fulfilling campaign with a completely different set of people that was also fulfilling. But it does take some real effort along lines that are often ignored or not seen for how important they are, compared to the more linear approach. (As stated, linearity is not bad, it is the false pretense of nonlinearity in a timely linear experience that is the problem.)
In order:
1. Three campaigns as a player, one as DM.
2. I mean, technically like 5 or 6 before? But been fairly consistent since the first time. I'm in a play drought for it, I admit, but I'm not having an issue running it.
3. Er... technically none?
4. Technically two dead ends, but both happened because real life got in the way, not because the game failed.
5. Oh, a handful. Anticlimax is not nearly the horror that so many make it out to be. Sometimes, it is good for a seeming massive threat to end up being a cakewalk. Those are things great memories are made of, so long as it isn't too frequent.
Not really. You just need to play with your cards face up as GM, explain to your players what you want out of the game and ask them to tell you want they want out of it, and set boundaries for what makes sense and what is warranted at your table.
My players do not fear random, permanent, irrevocable death, because I've told them that isn't a thing at my table. That doesn't mean they don't fear. Far from it! They've been extremely cautious nearly their whole campaign, with a few shining moments of throwing caution to the wind. But they are willing to act boldly when they care about things, because they know that I don't punish caring, I reward it—not necessarily with perfect success, but with new and interesting developments.
A willing, noble sacrifice to end a character's career? You're speaking my language. A desperate trip through the bowels of Hell to save a friend's soul, while they fight from the inside? O sweet Muse, sing to me! A ticking timer to resurrection, where you bring back knowledge from behind the veil of death, but cannot aid your allies in their darkest hour, and cannot know what costs they might pay for your absence? Sign me the hell up right this second.
That's how you address the problem of unresolved arcs. Don't let them remain unresolved! But also don't just hand them victory on a silver platter, because a pointless ending and an unearned ending are about equally disappointing. Instead, make every failure push things closer to a Dark Ending, and every success push things closer to a Golden Ending, no matter how small a push it might be. And every little, focused ending, a scene, a session, an adventure, forms another brick on the road to the ultimate conclusion. But the bricks will matter, because they'll be there due to the players' choices. They'll be there because the players decided what mattered to them, and gave it their all to seek it. The PCs will almost surely suffer and weep and bleed and swear rash oaths and do unwise deeds along the way. But they will also triumph and laugh and forge lasting bonds and save the day.
And together, you'll tell a story worth remembering.