The problem here has to do with profit. Since capitalism has become the most widespread form of economic process, it's always going to be the cheaper route, even if that means sacrificing environmentally-protective measures. There are indeed government limitations in place for many parts of the world, but even in the strictest regions, there are still plenty of elements in society that contribute to a poor environment. Then, of course there are those regions where there is little or no control whatsoever over pollutants and the like.
So will it get better? Most analysists will tell you that a change in social awareness will make that possible, or in overall global attitude towards the environment, or this-or-that. The reality is that such attitudes are not spontaneous, and do not come out of nowhere. As long as profit is in contrast with environmental concerns, the environment will be at the back of the proverbial bus.
So will it *ever* change? As we improve certain technologies, and reduce manufacturing costs, perhaps. Now and then, there are indeed scientific developments that work towards a cleaner manufaturing process, or that discover a more directly harmful property of a chemical or material, leading to laws regulating or banning said material, but usually there are things done to the environment that not only disregard it, but seek to use it abusively.
I'm not an eco-warrior. I'm neither Reuplican or Democrat. But I know that we are going to have more cancer and other medical complications and diseases in future generations, as humans, from pre-conception, to prenatal development, onto childhood and adult years, will be from the beginning exposed to higher toxins than ever before.
We'll either adapt or perish. Conceivably, population increases could ensure that the hardy survive, whereas population decreases, combined with this global toxicity, could, in a few generations, move us towards sterility and thus extinction.
Practical interstellar travel, a suitable colony world, and a thousand years of extra-terrestrial colonial development could indeed change this, illeviating the ecosphere on Earth, and balancing the human load. But there's a lot of BIG "if's" there, as we barely manage to get around the moon with human beings, and as far as we know for the moment, Earth is the only habitable planet, without the need of special manufactured environments like domes or mass-terraforming. Each of which we still lack the engineering resources to design much less construct.
So space travel isn't a guarantee. But we sure won't find out at the rate we've been going.