The problem that I see is that you aren’t very present in the art.

Now that depends on how much agency you give yourself, doesn't it? If you just give Midjourney a prompt and call it a day then yes. But the result won't be very good, will it? Similar how you could just input random notes to a synthesizer and get shitty music in return.

The problem is that the majority of people does exactly that and then shares the resulting images online, making it appear that is all there is to it. You can however express yourself artistically by using prompt engineering to get something good and than working with that to further approach what you imagine by editing the result. There are many people out there who could not artistically express themselves as they lacked the ability to translate their vision to a canvas. With the help of image generating AI they can finally express themselves. I think this is something beautiful.

How are we going to develope [sic] new styles?

While I do agree with you that our current AI image generators won't be very innovative, this is by design and not necessity.

This is what you would have gotten in let's say 2017 when asking an AI what it thinks a dog looks like (s. DeepDream).

And a couple years later you can achieve this with Midjourney.

Things are developing very fast and in the end of the day, even if we would never get an AI that can innovate art there is nothing stopping humans from just doing it themselves as we have always done over millennia. You can already greatly increase the creativity of existing image generators by tweaking the randomness factors and those algorithms don't just remix existing images, they are actually creating their own. You need the training set of existing labeled images to train the AI as it doesn't know what a frog is, nor a tree or anything really.

AI is just going to continue to remix remixes of remixes

This is indeed a concern. If you feed too much AI generated images into the training of an image generator it causes a sort of degenerative disease in the AI that results in inferior results. Some sort of AI incest so to speak. The prevalence of AI art on the internet and the inability to reliably differentiate it from human art is proving to be a challenge for making new training sets.