There's actually a very good economic reason to keep every species we can alive.
There's a lot that we can learn from nature - things that are valuable economically. Think of the environment as a massively parallel computer calculating efficiencies. The problem is, what might be efficient in terms of survival might not be what we're necessarily interested in.
For example,
In the same way, humanity has always looked to the environment for medicines. Antibiotics, analgesics, and anti-cancer agents are the ones you're most familiar with.
In the future, we will want to look at every possible variation on an enzyme. We're already learning about tricks to improve the efficiency of enzymes from comparative DNA analysis.
It's going to be a long time before we can throw in a genome and simulate the results on a computer. Having live species to examine will give us a wealth of data that will be useful for designing new enzyme systems.
Birds are a special case. The stress flight puts on an organism results in severe optimizations. For example, parrots poop every 20 minutes, simply to keep the flying weight down. The bones are hollow. The respiratory system is far more efficient than the mammalian system. The avian heart in most species has a range of normal sinus rhythm rates that would kill a human. The "bird brain" is optimized - African greys and crows are far more intelligent per gram of brain than humans are.
What right does anyone have to destroy the wealth of data that is the world around us? We're only beginning to glimpse at what millions of years of evolutionary computations has to teach us.
If you want humanity to meet it's end as cowards eating Soylent Green, you're insane.
The only rational hope is to see us emerge into the galaxy in triumph.
Ok, so we're probably going to stupidly kill ourselves off in the next
500 years (if that). That even one member of our race would say "waste their own time, money and resources trying to keep an outdated species alive" tells me that we're doomed by the marching morons.Maybe the cockroaches will succeed where we failed. One could hope.
Zooty