The only “sandbox” are the bullies burying the other kids up to their necks, taking away their toys - and when all else fails - pushing them out if the sandbox entirely.
High-sec = the sandbox
Wormhole space = the merry-go-round
Low-sec = the monkey bars
Null-sec = the jungle gym
The older kids thoroughly enjoy heading over to the sandbox to kick sand all over the toddlers. When that fails they like pushing the smaller kids off the monkey bars and chasing them all over the jungle gym.
I think when CCP designs something complicated it makes them feel smart. But they dont realise that if the game is complicated then people cant play it.
I think the biggest mistake was alpha clones. I havent paid enough attention over the years to say what patch or update was the issue that killed X gameplay mechanic, to me EVE is a game that you play until you burn out and then get the hankering for again in a year. But Alpha clones and the idea that EVE is a free to play game changed new player expectations for how the game would work and reward players.
Even buying the game is complicated Sometimes its $20 per month, some times you can get away with $15 per month, you can also play for free, or use in-game currency to pay. Sometimes they release a pack and you can use a spreadsheet to figure out if its a good deal.