2)Of course monopolies exist in tech and are bad, but that's the nature of the protectionist state capitalism in the US over the last few decades, and is not restricted to technology alone. Unfortunately corporations have more influence on the working of the government than the people, and we're now into an era of unprecedented corporate mergers and monopolies.
3)"Imagine if instead of claiming to offer us the best things in life, tech merely saw itself as providing efficiency devices. Its innovations can save us time on lower-level tasks so we can get offline and there experience the best things in life."
That's what a lot of companies do. Apple and Microsoft market themselves as selling productivity devices that help you get work done quicker. Jony Ive is on record saying that people use iPhones too much.
It's also not reasonable to sweep in hardware companies like Apple, who don't particularly care how much time you spend using their products as long as you buy them regularly, to facebook, who very much care about how long you spend on their site, since this is inherently linked to their profitability. What are facebook going to do, encourage people to log off so that they can live happy lives while facebook's profits decline? The purpose of a corporation is to maximise profits, you cannot expect companies which compete in the attention economy to compromise on that even if their services are addictive and not useful to the people who use them or productive to society.
If you really think monopolies and corporations like facebook are harming humans without offering any competing benefits, you'd have to question the whole system of corporate capitalism and whether we should allow corporations freedom to function without public influence over their activities.