Who's the bingus here?
Comparing Microsoft, Google, and IBM to AT&T and Standard Oil is completely bogus.
AT&T and especially Standard were indeed illegal monopolies. Standard, as you said, simply bought up the competition and build a vertically integrated business that made it impossible for anyone else to enter the market. AT&T built a vertical business by owning all the lines, either the long lines directly, or the local lines through the Baby Bells, and disallowing any hardware that wasn't manufactured by Western Electric, which they also owned.
No one was ever forced to use Internet Explorer; the option to install Netscape, Mosaic, etc. was always there. That IE was integrated with the OS and more convenient to the end user was completely irrelevant. That PCs on the shelves had Windows pre-loaded was also irrelevant; consumers always had the option to build from scratch and not have to buy the license for any OS.
If a company chooses to leverage their patents and charge outrageous prices as IBM did, that might piss the consumers, (at that time, universities, government, and large businesses,) but it's not illegal, and in the long run, is bad business practice. But no one was forced to lease IBM equipment; there were other companies making punched-card tabulators; Remington Rand comes to mind. Consumers simply preferred IBM, and were willing to pay the price.
Same with Ad Sense; there are other platforms out there, and a 10-second search, (using Google, no less!) comes up with at least a dozen alternatives. That Ad Sense pays better and is more effective then their competition doesn't make them an illegal monopoly, it simply means they're out-competing.
There's a world of difference between making it so that there is no alternative, (Standard Oil, AT&T,) and simply being the best competitor in the market, (Microsoft, IBM, Google.)