I think this is a problem that we need to confront first: Figuring out how to live in a sustainable closed system.
Were people ever successful in those bio-dome experiments? Are we now able to build an enclosed biosphere that can function sustainably, indefinitely, without bringing in materials or resources from the outside once you get started? There's not much point in trying to build something like that in space until we know how to build a sustainable closed system, reliably, without fail, here on Earth. Doing it in space will be more expensive, and failures will be less forgiving. It seems to me that we don't even know how to live sustainably within the biosphere we inherited, already running, the size of the Earth.
I guess you're asking, perhaps rhetorically, about the "Biosphere 2" project in Arizona. The short answer is no, not on either attempt, but some useful information was gained, which has spurred further, and rather more scientific, investigations.
The first group in there (1991-1993), although they lasted out the full two years of the experiment, experienced several 'rule-breaking' issues including: One member had to briefly leave the facility to be taken to hospital due to chopping off the top of one of her fingers in a threshing machine; Towards the end of the experiment oxygen levels within the facility had fallen so low that extra oxygen had to be pumped in, essentially in order to stop the participants' suffering severe side effects, possibly including death; Near-starvation was also an issue for the participants, though, I confess, I'm not sure if additional food was actually shipped into the facility.
There were a number of other issues that caused problems, but weren't strictly 'rule-breaking' in that they (probably) didn't break the closed system, such as: Fluctuating carbon dioxide levels; 'Plagues' of insect pests, notably red ants iirc; A schism within the group of participants, which ended in an almost complete breakdown in relations between the resultant two groups, to the extent that members of neither group would so much as talk to a member of the other group.
The second attempt lasted a mere seven months, with issues ranging from internal sabotage to external legal complications lending a certain 'colour' to the proceedings.
The facility is still in use, now under the auspices of the University of Arizona, and is being used for a variety of experiments, though much of it is no longer sealed from the outside. It does look like some actual science is being done there now, as opposed to what amounted to the public spectacle that occurred previously, so hopefully some useful insights will eventually come out of it. However, since some of the experiments currently running have an expected lifespan of 10+ years I'm not expecting immediate 'results'.
The key word here is "sustainability". Can we live in an enclosed system, indefinitely, without using up all of our resources or making it unlivable with our waste and pollution? It's the key to being able to conduct long-term space travel. It's the key to being able to build an off-planet colony. It's the key to continuing to live right here on this planet.
I do generally agree with you, but, I don't think we should get too hung up on the idea of an enclosed system, as that's not actually what we live in, and very unlikely to be what we end up creating. In the case of Earth, as a whole, we have an energy input, from the sun and we also have matter input, from in-falling dust.
In the event that we do create a habitable environment off-planet then almost certainly we will continue to ship additional materials to that facility. The occupants of that facility will almost certainly gather and use materials (water, minerals, etc.) from outside their immediate sealed environment. And in the near(ish) future I can easily see us bringing in useful materials from space, such as rare metals from asteroids, water, even hydrogen from our local gas giant.
Over the millennia, mankind has expanded across the planet, into almost every environment, but now, other than the oceans and to a lesser degree the poles, we're running out of new places to go. The only question is whether we have the imagination to spur further, off-planet, expansion, and the public and political will to make that a reality.