Losing experience on death to random shit makes me quit every league.

Losing your experience is not the same as losing your progress, because you can't de-level and the content you are engaging with between deaths is still advancing your character.

If I run 20 maps, die twice per map, end in the same place I started from an experience standpoint (zero percent of the next level), I've still made a few dozen chaos in drops from clearing those 20 maps. You can easily make far more through knowledge and juicing, but 3-5 chaos in profit per map is achievable by literally anyone and requires no game knowledge more advanced than "6 socketed items vendor for jeweler's orbs." I buy upgrades for my character, and then when I run the next 20 maps I maybe only die once every two maps because my character is now objectively superior to the previous version, even if I'm still the same level. Also, with the upgrades, I'm now clearing maps more quickly and dying noticeably less, and before long I'm up a few dozen more chaos. More gear upgrades, more maps, now I'm dying very rarely and steadily gaining levels. This isn't rocket science, it's the core gameplay loop of an action RPG: you clear content, you get loot, you improve your build by using or selling the loot, repeat until you're bored or the league ends.

Path of Exile doesn't take currency out of your stash when you die, which means it's never possible to lose more than 1/6 the cost you put into a map per death. No matter how much experience you lose, your character is constantly getting stronger because you're getting drops and your gems are gaining levels.

And that's before we even get into the fact that your maps themselves are constantly increasing in value and profitability over the course of a league. As you complete Atlas objectives, advance your awakening level, obtain/craft watchstones, unlock Atlas Passives, and so on you are directly and dramatically increasing the average returns from every single map you run, just by clearing content. You failing to gain levels does nothing to change that.

And finally, since we're already stating the obvious: if you have a character at a certain level and you can't beat a specific bit of endgame content, and you still can't beat it with a few exalts of gear upgrades, one passive point will not change that. You still won't be able to beat it, because the problem is YOU. Either your build is fundamentally flawed and needs to be fixed, or your combined mechanical skills and game knowledge are insufficient for the challenge at hand.

So, please, do everyone a favor, and stop parroting this nonsense about how you "lost two days of progress by dying." It's not true, it has never been true at any point in Path of Exile's development, and barring a dramatic 180-turn in GGG's game design philosophy it will NEVER be true. The only way to actually lose progress in PoE is gambling all your currency away, but that's another topic entirely.