They clearly are not doing enough. The thing i do when there is a cheating issue is that i play less and stop spending money on the game. People quit because of it. Games went down because of it.
They need to find big data solutions. Spoofers who want to get to lvl38 (the required level to max out pokemon) and a hoard of Blisseys have to teleport around to do it, when limting yourself to reasonable movement speed it is not possible, or it is very very slow.
Now the cheaters that leveled up and got their Blisseys before the cheat detection got more strict, and who now move very cautiously, they have to hunt these down by hand. No other way.
The way to do it is to keep certain logs, and develop data analysis that can find certain kinds of cheaters in the data, then you double check to make sure you are not hitting legitimate players, and then you ban them all at the same time. You do not ban them at the time you catch them, you build a list, then you whack them in a ban wave.
One thing may be important: Pokemons of cheaters do not get removed from arenas. Never. The account is banned, cannot be accessed, the arena pokemon stay. In my city, most gyms change teams every now and then, but some arenas drop to level 9, go up to 10, drop to 9, go up to 10, until they are full of CP 3300 or stronger pokemon. There can be old pokemon from cheaters in there. So real players actually team up to take down arenas that have grown into these monsters, some real players get their pokemon back, and cheaters as well as inactive players also get removed.
Arena space is limited, cheaters end up banned and have to start from zero, also some players quit, or maybe they just pause until generation 3 or another major update is announced. Arenas that stay with the same team for a long time get stronger and stronger.
To free up space for the players who still play actively and push the button each day, it makes sense to completely take down the very strong arenas every now and then. Can you rule out that the accounts behind the Blissey wall did not get banned or bored 2 weeks ago?
Arenas in my city actually got easier. You can find arenas to put in pokemon that are just 2800 or 2900, and they can stay for quite a while. If there is a really massively strong red arena, and you take it down, it will be a red level 10 arena again if some real red players live nearby, but the pokemon inside will be weaker. The active red players will actially be happy about the reset.
Niantic could help a lot, by simply doing arena resets every now and then. The players i talked to would welcome it. They could, for example, do it at the start of events. Just make the arenas grey and send the pokemon home and give the players a one-time bonus for the pokemon that returned that way. Inactive players and banned cheaters will not claim the bonus.
Arenas would be back to normal after 2 days in the big cities if they do this, except that lower level players with pokemon that are a bit weaker will now also find places inside. Bonus gets paid to active players because you click the button in the shop to claim the bonus. Heck, you do not even need the bonus.