[Nasrudith]

That is a list of where they are different but there are still areas of competition. Just because it isn't a one hundred percent overlap doesn't mean it isn't competition - otherwise one would say that GE isn't really competing with Samsung because GE doesn't make cellphones - ignoring the overlap of the appliance market.

Competing with large and broad corporations is a 'how do you eat an elephant' thing and they are increasingly prodding at each other for weaknesses. Trying to compete everywhere at once in prime specialties would generally be a losing prospect from the start even if they were willing to spend vast amounts of capital by mega corporation standards - not start up ones. You could compete with Apple on cellphones but trying the high end 'fashion' segment of the market would likely be a losing prospect as that is their prime specialty where they are established. Now if it is say Blackberry who has proven inept at their prime specialty they may wind up seized even by companies who aren't even trying for their niche.

Voice assistants aren't even limited to just Apple and Amazon, Google, Microsoft and even Samsung are trying to get on it. Apple is trying Apple media again and Apple, Amazon, and Google all have their own music stores for one. They may not be as prevalent relatively speaking but they aren't just letting each other keep their specialties.

I suppose part of this also has to do with definition of monopoly and it being versatile. Technically speaking owning a grain field, mill, and a bakery is a monopoly - a vertical one. You have to be able to compete with their own grain production costs and milling costs in order for it to sell wheat or flour to their bakery - otherwise they would just use their own as cheaper.

What are referred to as tech monopolies trivially have comparable alternatives but people don't go with them. You can host your own email or have anyone hosting video data - they just won't be the behemoth in the room. I suspect there may be some talking past each other.