Berkshire Hathaway (BRK.A -0.16%) (BRK.B 0.11%) has produced amazing returns for long-term investors under Warren Buffett's leadership. However, at a more than $1 trillion valuation, its ability to consistently generate outsize returns from here is somewhat limited.To put Berkshire's success into perspective, if you had invested$10,000 in Berkshire Hathaway 40 years ago in 1985, you would have nearly $4.1 million today. And that's if you had bought shares two decades after Warren Buffett took the reins and ...