Can only speak from my own experiance, but please no to the easier money making...I recently finished all the challenges on jurassic and even on the last map which is definitely the hardest to make a profit on I ended up with 600k+ profit per minute and over 50mil in the bank, so it's not too hard at all to make money. Especially on the lower difficulites it's just as easy to make profit if not easier than in the first game when your amenities are set up right.
I also don't mind some expeditions being that expensive, they're supposed to be big hitters and stars for the late game when you already got a decent income and profit going to easily afford them, so of course you shouldn't be able to get them right away. Also think JP Chaos is kinda a hit and miss with RNG regarding storms and all. I had some bugs going around the first time and could barely finish it so I tried a second run to see if it was the same and finished it in about 2h without any problems whatsoever. So if the Frontier people had a playthrough like my second run I can see where the 2/5 came from, if it was like the first and what others seem to experiance I really don't see it either.
No, it shouldn't cost over 2 million or 3 million for an expedition for a Rex. The 1.6 million for the Iguanodon was bad enough. Money is far too tight in this game. Like I said, it shouldn't be as easy as it was in the first game but shouldn't be that hard either. It just makes playing it a frustrating grind or chore. It starts becoming less fun. It needs a slight rebalance.