This is all true, but simply by requiring the bots to perform quests exposes many more of them to players who will be able to report them.
I’m a bit skeptical that someone could create a bot that could pass as human through 100 levels worth of quests… the technology is not quite there yet. Eventually though? Sure. But now is not quite that time.
EDIT: if only 1 out of every X number of bots can make it through the gauntlet, I imagine that has to impact profit margins.
Of course it impacts profit margins, but the break-even point is very low. To give you an idea for diablo3 the breaking point was 30 hours after leveling. Leveling took me two days back in the day.
Most of my bots survived a month initially and then it went down to 14 days at the lowest. So you can see it is a daunting task, but botters have to be fought not on the market but every minute after their creation.
Last I saw was 400k for 2-3$. The game is at 9.99$ (probably half of that if you want to) and so if you have a bot just farming 50k per hour you would break-even after a day. I think even the spammers survive longer than that right now 
I think you’re quite right about your assessment of the break points. There is completely inadequate enforcement at present.
What you are explaining is known to me in regards to path recording. I am curious as to how you would think a bot could be programmed to interact with game objects that have entirely random (and some pseudorandom, which is not as strong) locations in a zone map, or in a set area? There are a lot of quests with these, and many of them cannot be interacted with using game’s targetting system, requiring either a manual click or standing on point with them to use.
The only way of handling those is really large, redundant looping paths combined with parsing packet info to provide the bot with coordinates to seek, aka map hacks.
These and late-game solo boss fights seem like the parts that would present bots with more trouble, although I expect boss hurdles could be solved by using specific classes and builds with strong forms of passive mitigation or fast ability-based kills.
First off: When a player clicks on the object the interaction is a simple “command”
You rightclick it, but it will likely be handled by the game in a fashion like “interact with object X”
The bot would go close, trigger the interact routine on object x. It isn’t using the mouse. The bots are not running randomly into a quest and learning to do it as they go. A human does the quest and decides how to let the bot handle it.
You’re right often combat is a weak link of a bot, but it depends. WoW bots can be quite strong and I know a dozen people by now for example that use a bot while !raiding! to maintain maxDPS rotation, dodge mechanics etc.
These are specialized things though, the typical grinder does not have a sophisticated fighting routine running.