Sure, just tell me what environmental changes will take place in the future and what features that the modern snail lacks to deal with these changes. Your question is akin to me asking you what color hair your great, great, great, great grandchildren will have. You have no way of knowing now who subsequent generations of your descendents will marry and have children with. Therefore, at this time it is impossible for you to even pose a reasonable guess as to the answer to my question. That doesn't mean that the laws of genetics don't work. It just means that you have insufficient information to answer such a question. Similarly, there is insufficient information available to determine the future evolutionary course of any given modern organism. As I said earlier, absent any changes in the environment that modern organisms aren't able to currently deal with, there should be no evolution. Evolution makes no requirement that ALL species must undergo major changes over time. If an organism is well suited to its environment and that environment doesn't change, then that organism will remain relatively unchanged.
Well! I'll be a monkey's uncle! You sure said a mouthful there! But with all the hundreds of millions of years of evolutionary evidence and records of enviromental changes and predatory changes and all the history of all past changes if one wanted to could one SPECULATE on what that robin go after that worm will be 500,000 years from now? Is that enough time for him to speciate a couple of times? (my new word!)