Well you've described the faith behind macro evolution. That given enough time small changes translate into entire animals evolving from one to other. Sort of an inverse 2nd law of thermodynamics. This is based on sheer speculation and faith and no evidence.
So the proper question is - what is the evidence to support macro evolution? Evolutionists have to prove macro evolution exists. I don't have to disprove it. Your logic is nuts.
No faith is needed. Small changes accumulate within a population, selected for by environmental and other pressures. Over time, isolated pockets of a population will accumulate changes not reflected in other populations and because of this will no longer be able to interbreed with those other populations.
Not really. You already accept that changes within a population occur. That's evolution. We're simply saying that there is no magic cutoff beyond which no more changes accumulate.