Your assuming that poker software (holdem manager, poker tracker) are only used to monitor live play stats and make adjustments based on reads of those stats. Although this is an important part of what the software does, you fail to think of the amount of post/pregame work you can do reviewing hands and adjusting your play based on your stats over a longer term to find your own leaks.

Also, when playing live you have maybe 9 people to remember and learn about, playing multiple tables online where you could have between 9 and 79 opponents you cannot rely on your memory to keep track of what people have done 20 hands ago, let alone 2 hours and 1000 hands ago.