There is no hosting monopoly, there is no payment processing monopoly, there is no domain registration monopoly, there is no SSL CA monopoly.
Yes, there are cryptocurrencies available, so if we can fully legalize it and promise that we don't touch anyone's private transactions (as well as businesses officially accepting crypto) - that would be an argument.
For better understanding how bad it is: it's non trivial to even accept worldwide payments for small business/individual in the internet if you are, say, from Ukraine, Russia, China or lots of other countries not processed by stripe/paypal for some political or legal reasons. Apart from that, there is a "free" market of two payment processors in the internet and two card processors =)
It's perfectly normal in Europe to pay for your ecommerce purchases with a bank transfer directly to the merchants account. There are thousands of banks out there, there's no monopoly or oligopoly at play.
However, there clearly is a small number of players in mobile platforms, cloud, and payment, and they act in a unified way. It has been sufficient.
Sure, there are in fact only a small number of players in this space.
>cloud
There are vast amounts of hosting providers. A quick google suggests over 300k, but that sounds somewhat unlikely.
>payment
There are a thousands of banks in the world, most of Europe manages just fine using bank transfers for payments without involving external payment processors.
>It's sufficient to push undesirables to services which are more expensive, more inconvenient, unreliable, and so on. Relegate them to their internet ghetto.
Is this really a problem? That's just the inherent nature of being undesirable.