@exiliaex

i think one thing that is important to consider is the historical/social context in which some invasive plants get introduced.

for example, some plants like Ailanthus altissima (tree of heaven) which were brought by europeans to the americas from east asia, as part of an exotic plant trade -- this in itself was treating a piece of an ecosystem as an extractable commodity; a piece of larger dynamics of colonialism/imperialism.

similar with kudzu; introduced partly for the same reason, but also, promoted by the u.s. government in the south as a kind of quick fix for land that had been fucked over by cotton monoculture cropping -- so, an instance of the capitalist/colonizer creating the problem in the first place, and mass death/displacement/trafficking/enslavement of african and american indigenous peoples to do it -- and then attempting to solve it, by bringing in this new plant, but *still* not working in a reciprocal way that actually honors the ecology of where it is.

or: white mulberry (Morus alba) being brought from asia to the americas by european colonists, in a failed attempt to start a silkworm industry.

there are many other examples of species migrating without the same ecologically unbalanced impacts (i remember the book "the next great migration" by sonia shah talks a bit about this, IIRC)
and also, examples of people, particularly diasporic / displaced peoples, migrating and bringing their food plants with them (there's some evidence that this was how american lotus, Nelumbo lutea, spread to regions it hadn't been before -- because forcibly displaced Indigenous people brought it with them.)

so it's not that ecological migration and transformation in itself is "bad" -- but, there's very particular contexts in which these things happen, and oftentimes, with plants that become invasive, the context mirrors human patterns of forced displacement, extraction, and neglect of our role with the ecosystem.

and, as you already said, there's the importance of biodiversity. plenty of introduced species don't become invasive.

i do think about this stuff a lot and i think there is some room for figuring out what exactly will be the role of these species, and how people will deal.

like, for example, people have become really eager to exterminate the spotted lanternfly on principle. i think this is not exactly seeing the whole picture. there's been some evidence i think that they are not as harmful as some info had previously suggested, and they may help to provide a control for their preferred host plant, the tree of heaven? (idk if you've tried to deal with that one in an ecosystem or garden context - but it's pretty hard to do any other way, besides, i've heard, herbicide.)

or like, there's a Crime Pays But Botany Doesn't video where he shows the ecology of a parking lot. he points out that a lot of the early species that are getting a foothold between the cracks are invasive, but he muses that over time, their biotic matter will build the soil, and maybe some resilient native species will take hold.

i don't think that restoring things to a perfect state of the past is exactly the goal. i think, as you're getting at, there's always some state of change. but also, it's about the larger relation to the ecosystem and to each other.

@exiliaex
I like to only use "invasive" to describe the dynamic you described first, and use "exotic" for species that are not invasive but also not native. So many of the food plants I grow are exotic, but if they escape my garden they won't be invasive, they probably won't survive.

Cats are invasive, dingos are not, and can now basically be described as native (naturalised).