One of my internet friends actually bought the game, and has been playing it. She did all the content in the game, which got her to level 38 out of 40, and ground the rest of the way. Now, she has helped me understand how the top-tier gear works.
As I understand it, the best gear in the game is UNITY gear. You can't get UNITY gear as drops, nor can you spend game money for it - no, to get UNITY gear, you have to accumulate and spend UNITY merits. You get UNITY merits by, of course, doing UNITY missions.
Once you're 40, you get invited to the UNITY HQ, and a guy there will give you randomly-generated repeatable missions. He'll go "Hey, there's a thing here!" and you go there and then you slog through a random instance. This gives you 1 UNITY merit. After you've done five of those, he goes "Hey, there's a big thing here!" and gives you a 5-man raid thingy. You, and up to four others who have also gotten their 5-man raid thingies unlocked, go in there and fight through and win the raid, and each get 1-3 UNITY merits from it. And that's it for the day. This can be repeated daily.
So, 6-8 UNITY merits per day. Okay. You have 9 gear slots, and the best gear for all of them is UNITY gear, so you want 9 pieces of UNITY gear. I don't have the exact prices, but UNITY gear costs between 250 and 1000 merits per piece. Apparently, on average, it will take close to 500 days of doing these random cookie-cutter UNITY things every day to get all your gear.
I will never complain about CoH's merit grind again.