I repost what I said earlier in answer to the Very Harders.
Moving to VH is not a valid answer to the problem.
I regularly lose campaigns in normal, or to say better find them unsatisfying. I don't like to struggle a lot and I don't play to overthink anything unless I'm going for a specific and hard achievement. That's why I barely touch VH, I did less than 5 campaigns on it and the hardest country I played in VH was the Great Horde. And even with that, I still think I'm part of the fraction of players who often starts as OPMs in ROTW (albeit in normal) and who got some of the most difficult achievements. Judging from that and from what I read, I think the vast majority of the player base does not want to play in VH. Maybe it's laziness, maybe the ego, I don't know.
To me at least, it's not that the game is too easy pre 1600, it's that it's too easy post 1600. If I bumped the difficulty level, it would undoubtedly be too hard pre 1600 (unless I sticked with majors).
The heart of the problem is not that people drown in money, it's that the only way to spend money is to wage wars and to deal with revolts, which is why only putting the game in VH will help with the money flow. But that's not the same early game experience at all, and wanting a different post 1600 experience does not mean wanting a different pre 1600 experience.
It is extremely important that it is still possible to play in Very Hard and not significantly harder (or not harder at all), still possible to strech yourself super thin and to merc swarm if you want to One Tag as a ROTW OPM in normal. That's why I agree that wars should not be more expensive, unless it's part of an interesting mechanic tied to a better professionalism.
BUT at the same time there needs to be a way to spend money mid to late game if you play in normal and are successful. And achievements designed about this to make it valuable. Patronizing works of art, creating infrastructures, spending money on public welfare. Anything that would feel rewarding, interesting, that would not harm someone not going for it, but that would be an alternative to just paint the map with the excessive money a moderately experienced player would have if he plays in normal. Devastation and Prosperity is a step in that direction, but tbh I totally ignore that unless I want to develop for an institution or I have a goldmine early game, simply because it's a passive mechanic. Something along this line, on which you could spend money, could make tall play and a peaceful game once you secured a nice trade network and unified your culture group interesting, even if still less optimal. I miss the days where I was bad and could spend 3 years waiting for a church, and still feel like I was building my country and having fun. Now I built all possible churches and I drown in money after 100 years so boredom pushes me to paint the map, while in my heart I would be more of a tall and stable player if you actually had anything to build.