I disagree. Sort of.
If you want to put money into the game then yes, you will get their quicker and with more powerful creatures. You can buy boosts and incubators. You can burn through the game and for many, will just get bored and ditch it. If you don’t spend out on incubators and boosts, you can enjoy the game on the way up. You’ll get there and you’ll earn it.
I agree about the very top of the Arena ladder. That is for the players willing to pour the GDP of a small country into the game to do so. Is it worth it? I don’t think so. You can can happily be F2P or P2W and enjoy the game. I don’t care about climbing to the top (I’m still amazed I got to Aviary recently). I’ll continue to enjoy playing the game as I do.
It comes down to what sort of player you are. There are competitive types who happily fork out the cash and battle in the high end of the Arena. There are casual players who happily play the game, collecting dinosaurs and making hybrids. There are players in between, who likewise enjoy the game for what it is.
My point is that you play the game how you want to. You don’t have to spend the cash and burn through the game, missing the scenery on the way. You can earn it the hard way, getting where you can and enjoy it without forking out cash if you don’t want to.