Furthermore, while Al Capone could have found other crimes to orchestrate to make himself rich, he wouldn't have been able to perform those crimes as well as liquor smuggling, limiting his supply of cash (lets face it, he was probably doing those things in our history timeline as well as smuggling).
Alternatively, if we suppose some crime that he really did neglect in favor of smuggling, why did he neglect it in favor of smuggling? Because it was not as profitable or carried greater risk (in our history timeline, he was able to manage his risk effectively. He wasn't killed in the act and was only eventually caught for tax evasion. Had he been, say, robbing banks instead, he undoubtedly would not have lasted as long.)
Any way you slice it, prohibition made dealing with Capone worse than it otherwise would have been.
Alternatively, if we suppose some crime that he really did neglect in favor of smuggling, why did he neglect it in favor of smuggling? Because it was not as profitable or carried greater risk (in our history timeline, he was able to manage his risk effectively. He wasn't killed in the act and was only eventually caught for tax evasion. Had he been, say, robbing banks instead, he undoubtedly would not have lasted as long.)
Any way you slice it, prohibition made dealing with Capone worse than it otherwise would have been.