2. Building a spreadsheet program is a ton of work, but it's also a multi-billion dollar market. And a proof of concept can be built by a couple of smart hackers -- but it needs a good hook of course. Reality: very few people even try.
3. When a ton of money is spent on marketing then that is strong evidence for lack of competition. After all, all money spent on marketing would otherwise go directly to the bottom line. This is why restaurants (fierce competition) spend almost nothing on marketing. They can't afford to. Fierce competition => low margins => no marketing budget. Reality: mediocre products and tons of marketing.
4. The advantages of the internet are not capitalized on by everybody, as I've been saying. The opportunity is there, but people still have to take it.
This is because it's a sucker's game. You can build the best spreadsheet in the world and Microsoft will still eat your lunch. The expected returns on a goldfish-selling business are higher. LibreOffice can't even manage to give away a tenth as many as Microsoft sells. Like, yes, building a spreadsheet program is something people could do, but it is not an idea with even the remotest possibility of making good money.
I think I have figured out the fundamental disconnect here. You are talking about how easy it is to build stuff these days, while other people are talking about how easy it is to make a living off stuff. It is easy to build things. But building something alone is pure cost, no profit. Then the hard part comes. The difficulty has just shifted around, not disappeared.
3) No, just the contrary. Try yourself to gain traction with a free open source software and see how difficult it is.
4) That's what I said but it's being capitalized by a lot of people
1) Startups and small business are popping up everywhere and the majority die.
So maybe launching a general Excel competitor is a pretty daunting task because you're going up against the gorilla of the market. Targeting a specific subset of its user base can still make for a viable business.
But you are underestimating by a lot the costs and risks of software development, for example, a spreadsheet competitor. Not only from the software development side but also from the marketing/sales perspective. If you analyze an established software company the work force in software development and marketing/sales are evenly distributed and this is not because companies love to make advertisements, events, etc but because is how (currently) the business world works: you compete in an attention economy and this costs millions.
Another thing that you are underestimating is that Internet makes much easier things that were impossible or time consuming just a decade ago but "everyone" is competing in a new league and that advantage will be capitalized by "everyone".