The law of large numbers has to do with statistical sampling, not with determining company fundamentals. It says that as you increase your sample size you're more likely to get a "true" value. It has nothing to do with stock pricing. Or company earnings, growth, etc. It doesn't mean that as a company grows, that incremental growth becomes more difficult. Frankly, it's irrelevant for predicting what a company's fundamentals will look like at any period in the future.