Being able to produce something in the lab is completely different from it happening in nature... If anything it would prove intelligent design by showing that a huge amount of intelligence must be put into setting up an experiment just right to get 2 of the 4 nucleotides created out of your mud mixture.
Well, it took billions of years to happen in nature according to science, didn't it? I think few scientists would be prepared to wait that long. Besides, since we don't actually have access to what Earth was like 3 billion years ago, there's no way to set up these experiments without "a huge amount of intelligence", but this doesn't in any way prove intelligent design, just that finding out details about the past is really darn hard when they're not written down somewhere. Imagine if all Civil War records were lost and you were trying to recreate all the battles' results by simulating them o_0
I don't really see why people like to insist so heavily that abiogenesis is something completely separate from evolution except that they want to bracket off the part of life's origins that has the most holes so that they can still say that evolution is strong.
But they're not really one theory, even if many Christians think they are. I can't understand why people like to insist so heavily that abiogenesis is somehow part of evolution. Abiogenesis is the answer to "how did life start" and evolution is the answer to "where did all these differences between species come from"; creation might answer both questions in one fell swoop, but that isn't necessary. There's nothing contradictory in believing one without the other, and while I have no clue how a scientific person could disagree with the theory of evolution I think it is quite reasonable to disagree with the theory of abiogenesis. Unfortunately science doesn't allow for supernatural explanations so there is no alternate theory for abiogenesis. Personally I think the most reasonable religious approach is to believe God seeded the planet with life so evolution could start (accepting Genesis as storytelling rather than literal historical fact).
The truth is that abiogenesis is almost completely guesswork (because of the difficulty of replicating conditions back then, of course) whereas both microevolution (changing a trait within a species) and macroevolution (changing species over a longer period of time) are extremely strongly supported by evidence. Microevolution has even been shown to happen in a controlled laboratory setting.
Most Christians believe the obvious scientific evidence that creatures to change and evolve in response to their surroundings but that those changes never result in the creation of a completely different kind of organism. Like a land mammal isn't going to evolve into a sea mammal but you can get different types of dogs, bacteria becoming immune to medicine and so on. This Microevolution is normally confined to species or the biblical word "kind" for different kinds of animals.
But how can you conclusively define what kind of animal something is? Recall the heap paradox (is 1000000 grains of sand a heap? yes? how about 999999? etc.) - when a group of organisms change species there are pretty much always some kind of intermediate forms that aren't clearly one or the other. In every small change it won't look like the two organisms are of different types, but if you add in a huge number of changes it might not be so obvious. You can tell fish and land animals apart, but what about the
lungfish? What about amphibians? It's not like we only had sea animals and suddenly land animals popped up, but rather that some sea animals slowly adapted to become more and more able to take advantage of land, until eventually at least one group of animals was so comfortable on land that they didn't need to go back to the sea at all (and would eventually evolve out of their now-vestigial sea adaptations). Distinctions such as "land vs sea" are never really clear-cut in the same way you can never objectively say the exact number of sand grains you need to make a heap.
Anyway, even if such huge chances are hard to imagine, it's possible to imagine two species developing from one by considering two separate groups of the same species living in different environments. Remember that one of the main definitions of whether two species are different is whether they cannot reproduce and make fertile offspring. So suppose that one of your groups stays mostly the same, because they're fine in their environment, but the other group had a hard time and has gone through a huge number of adaptations in the several millions of years it's been in the other environment. Now they meet up. It's quite reasonable that enough small changes could have taken place that the two sets of DNA are just incompatible - then you have a new species.
