You most relevant point is "Who knows, maybe the demand for snake game would not fall if new "blocks" game was not born. "
I think you can elaborate on these line -
1. The weak analogy between company a and b
2. The difference between the marketing strategies between company a and b and the target audience
3. The failure which caused the downfall of company B but will not be likely in case of company A
4. The competent management, expansion goals, efficient product differentiation and looking into ostensible markets by company A
5. Any prediction about the future is wrong unless backed by evidence to substantiate the claim. Hence the argument is weak and relies upon distorted data and vague assumptions.
6. To strengthen the argument - the argument should do blah blah. The argument does not offer evidence to substantiate the claim that company a will fall.
7. In conclusion, the argument is weak and unconvincing as it stands.
Please press kudos if you like my post.