In terms of paying for progression, that is kind of true, but its really expensive and is not 100%.
You can buy costumes for real money and turn them into crons, those crons let you safely try to enhance gear without it degrading if it fails. PEN rolls are usually around 3% no matter if you pay or not.
Currently its really easy, the easiest it has ever been to get to softcap. TET boss armor and TRI yellow accessories.
I think it's the same with any mmo, but you can buy stuff to help speed you up a bit. (Costumes that provide bonuses like -2s cooking time, or +20% EXP)
I personally don't think they're that worth it since you can literally just afk the lifeskilling stuff and that there is a limit to how much you can reduce that time.
Leveling in the game is still the same, really hard past 61. Though content is not entirely locked to your level past I believe 60, your gear is the only thing really stopping you.
Seasonal servers has honestly been one of the best things that could've ever happened to bdo, enhancing the season specific stuff is a lot easier than normal enhancing and it doesnt cost any monetary investment to get into it. When you complete the seasonal pass thing they have, you can graduate the season character into a normal character and get some bonuses. The bonus includes a coupon to convert any seasonal weapon/armor into the boss grade equivilent - 1 level, so PEN Chest = TET boss Chest, the stats are the same.
You also get stuff to turn all of the seasonal stuff into non seasonal so u can use it on any normal character, you just cant further enhance it.
I've mostly done lifeskilling so I'm not entirely clear on what is at the end-endgame.