The more appropriate time window is from 2008 to now, since that has been when Gates was absent from the company and when Ballmer truly ran the show on his own. Over that time the stock went from roughly $28.5 to roughly $34.5, while giving out a total of $3.51 in dividends per share. Inflation has a slight but non-trivial effect (adjusting that $28.5 stock price to about $30.9 in today's dollars). Overall you get a total rate of return on MSFT stock of about 23.5% over that 5 year period (even adjusting for inflation of the value of the dividends).

That works out to an annualized return of about 4.3%. That's better than a punch in the face but it's not that great compared to any other similarly sized tech company in any related industry.

And inflation. Dividends averaged 1.5% during this period, inflation about 3%. So really we're looking at a ~15% decline in value.

No, inflation is irrelevant to whether owning Microsoft was a good or bad decision. You want to compare to an alternative investment, such as treasury bills.

Inflation is only relevant if you want to see how the purchasing power of Microsoft owners changed.