It is the banker who, after the passage of fifteen years, thinks of the original bet as wild and senseless.
And this wild, senseless bet was carried out!
It is wild and senseless on the banker's part because he is putting up two million rubles against nothing. There is no quid pro quo. If the lawyer defaults on his part of the agreement and leaves his confinement before the fifteen-year term is up, then the banker gains nothing, and he is out the expense of providing for the lawyer for whatever time he spends in solitary comfort in the banker's guest lodge. On the other hand, if the lawyer sticks it out for fifteen years, the banker loses two million rubles. When the story opens that sum of money means a great deal to the aging man. If he pays the lawyer he will be ruined. He is seriously considering murdering his prisoner, thereby becoming a murderer and a scoundrel at the same time.
Fifteen years before, his millions had been beyond his reckoning; now he was afraid to ask himself which were greater, his debts or his assets. Desperate gambling on the Stock Exchange, wild speculation and the excitability which he could not get over even in advancing years, had by degrees led to the decline of his fortune and the proud, fearless, self-confident millionaire had become a banker of middling rank, trembling at every rise and fall in his investments.
On the lawyer's part, he is giving up the best years of his life on the chance of making a fortune. If he decides he can't stand the solitude and vacates the lodge voluntarily, he will have lost years of his life for nothing. If he stays there for the full fifteen years, he will have won two million rubles, but in effect he will have sold fifteen years of his youth for that amount of money. And in any case, the bet would have proved nothing as far as penology was concerned. As the banker reflects in Chekhov's long exposition:
"What was the object of that bet? What is the good of that man's losing fifteen years of his life and my throwing away two million? Can it prove that the death penalty is better or worse than imprisonment for life? No, no. It was all nonsensical and meaningless."
The bet is indeed "wild and senseless." Chekhov wanted to write such a story because the idea appealed to him (just as it appeals to readers)--but he had to make it plausible. He does this mainly by having the banker himself acknowledge that the bet was wild and senseless because it created a lot of trouble for both men and proved nothing. This is for the benefit of the reader--that is, to keep the reader from thinking the same thoughts himself. Nobody would ever make such a bet. Nobody would want to spend fifteen years in solitary confinement, and nobody would want to keep another man a prisoner on his own property for fifteen years. The story is implausible, but Chekhov was a great writer and made it not only plausible but memorable. We actually believe this happened. We can sympathize with both the banker and the lawyer. We are appalled by the ravages of time. The banker has become old and fearful and unscrupulous. The lawyer may think he has achieved high enlightenment, but he has lost all his youthful vitality and optimism, and he looks like a corpse. What good is the rest of his life to him? Where will he go? And he doesn't even collect the two million rubles!
It truly was a wild and senseless bet. But both men seem to have gained some wisdom and humility from it.