missed dividends
the possibility that Microsoft grows its profits more
the possibility the stock keeps rising, and then even if it falls, it's still higher than the price you sold
The last reason is why timing the market is so hard. Had you sold the S&P 500 in early 1996 because it was 'too expensive', you would have never been able to buy back at a lower price, ever, even after the crash of 2000-2002 and 2008-2009, and you would have missed all the dividends.
It's not the new normal. That's what people say to justify extreme premiums during times in which investors have overly inflated valuations. This is the third bubbly tech era in the last 20 years. That new normal premise has been used frequently in each.
I understand why Microsoft has inflated. It doesn't jive with actual results in the post Ballmer era. There isn't even a hint of the kind of growth that could justify such an elevated PE ratio (elevated for a company with no growth for years). Their fast growth areas are struggling to off-set what they're losing in eroding, old business franchises. Net result, they're standing still.
"We delivered $90.0 billion in revenue and $22.3 billion in operating income this past fiscal year. Adjusting for Windows 10 revenue deferrals and restructuring expenses, revenue was $96.7 billion with $29.3 billion in operating income."
That is 31% more revenue and 34% more operating income compared to 2012 (the 5 year time period you're citing). Stock backs will also move the price -- there's almost a billion fewer shares outstanding now than there were 5 years ago.
Of course, investors buy companies for future performance and not for past performance. I would suggest that investors like MSFT's current strategy and management considerably more than their past, and as the management continues to increase profits, investors gain more confidence.
Microsoft for example has barely grown its income in a decade. On what planet should they have a 28 pe ratio? The stock has tripled (!) in five years on the back of zero income growth. It's massive value destruction just waiting to happen. Shareholders will not just sit, hold and tolerate the inevitable value destruction that is looming, it doesn't work as insurance at all in such a context.