IBM was a much bigger and more domineering monopoly at it's peak - there was a time where you effectively could not have computers or a datacenter without paying IBM money, directly or indirectly. I wouldn't qualify most of the FAANGs as monopolies (at least not yet) - reasonable substitutes exists for all of them.
The modern market does favor a handful of large players for each market - this is true in almost all sectors though. This not a monopoly though; as long as the top players change over time it is still a working market.
The modern market does favor a handful of large players for each market - this is true in almost all sectors though. This not a monopoly though; as long as the top players change over time it is still a working market.