Well OP the issue is that thread isn't asking the right question, Africa and Asia have local game consoles. The real question is why there aren't any new "INTERNATIONAL" entrants in the gaming market and that's a simple question to answer.
Due to regulations, guidelines and other issues, the amount of money one company would have to spend just to have decent stock internationally would be much more than what it would take an American or Japanese company to do. In this case, most countries are rigged out of the race.
So that only leads some companies in a select part of Europe, America, and Japan (though the barrier is rising up there) that could even put out an international console without as much of an issue, relatively. However, even these countries aren't putting out new consoles, why? Because gaming got too big, complicated, and expensive.
What do I mean by "too big"? Well, simply that Sony, MS, and Nintendo expanded their platforms during the Xbox/PS2 rise and that continued with the 360/PS3 and the current consoles now. A company would literally have to crate a new platform, start from scratch and spend a ton of money on an outreach campaign to even have HALF the infrastructure in place to be a success. Margins are already low on gaming consoles as is, so that would be a disaster.
One of the 3 would have to mess up sooo bad, that a competitor could grab victory from their ashes. Or drop out. Even then they would still have to spend tons of money catching up with the software support and infrastructure.
Gaming as of now, is locked to these 3 unless a bigger company wants to lose massive amounts of money they will never get back. Companies aren't willing to write-off high millions to low billions of dollars just to enter, let alone spend more money to be competitive.
When the Xbox original lost billions of dollars the signs were already there this industry was a done deal. Android consoles tried to find a niche to penetrate on the side but that ended up not being viable.
Back in the day a competitor could come out with a new idea, get some software support, offer a unique service (or games), or graphical process, and be able to start building infrastructure and retail support quickly. Make deals with third-parties, able to get some exclusives by default, spend a bit if they wanted to grab more, able to have a decent relationship with retailers without things costing too much, manufacturing was cheaper, etc. Console specific features weren't overly expensive to maintain, etc.
Now half of that costs an insane amount of money, and profit margins are smaller than ever. Console feature and online infrastructure costs way too much, Third-party deals cost way too much retailer contracts coast way too much. Translation and distribution along with marketing costs way too much. Game and hardware development costs way too much. Etc. etc.
This is why people saying "Apple, Google or Amazon are entering the industry" don't make sense, they aren't going to traditionally compete they are going to enter to set the stage for the destruction of the traditional console model and hope to take a slice of the pie decades from now when everyone has streaming boxes. Unless you think those companies want to lose a crap ton of money they likely won't make back and have some financiall damage done to their bottom line.
The fact is, unless one of the three gets brought out buy another company, or someone is crazy enough to enter losing money they won't get back, the next time their are "new competitors" in the industry will be when traditional consoles are dead 50 years from now and everyone has streaming boxes. No ones going to try coming in as a 4th party to enter the industry, this was a big issues last gen, now it's even more of an issue.
So unfortunately the days of competition are basically over.
To think what Nintendo could do without having to lower their power levels would be insane. I mean look at how their games run/play/look on Switch, now imagine if they have next gen power... yes please.
