True, controlled by corporations or individuals except a few. XRP is an example of a coin that could be drastically changed and the coin owners would be left in the cold.
As a kid I once flew a kite with almost 1,500 feet of kite string. A quarter mile or so. It sagged quite a lot but we estimated it was about 350-400ft up or so in a field. Then a crop duster showed up.
I put the string between my legs while a fiend held the spool and ran as fast as I could to bring down the kite.
We were also about 1 mile past the end of a air force runway.
Etherium, Solana...etc are the next level of more risky networks. They have distributed upgrade/change protocols as well but are not as decentralized as bitcoin. As for how efficient a coin is, I am not comparing that metric as efficiently does not correlate to risk. This post was just referring to risk.
If you do not know a lot about "crypto" then I would say the main thing to understand is that there is Bitcoin (not owned by any single entity) and then there is everything else. Other "coins" are owned by corporations that can make decisions about it and change it to some extent. These are extremely risky.
Bitcoin (btc) does have risk but much less. It is not owned by any company or person or country. It is like the internet, only exists because tens of thousands of internet providers(miners for Bitcoin) around the world make it possible. Bitcoin has, in its codebase, a limitation that any change must be agreed upon by 95% of these providers(miners). This way security patches and bug fixes can be added because everyone agrees those are good. Other harmful changes would never reach 95% agreement therefor could never be implemented. There is a limit of 21 million Bitcoin and this number can never increase unless 95% agree to it... which they never would. This is in stark contrast to normal money which is constantly printed(at random rates depending on who happens to be in control at that moment) so that the supply increases making its value drop.
Scamming happens with cryptos, Bitcoin, euros, dollars,yuan... and always will.
$6 now. What about 15 years ago? Rent in the city is $181/mo? That would be for a 1 bedroom outside the city. Double that for room for a family and you might be able to just get by paycheck to paycheck. While living in a polluted city(another money saving tactic)
Edit: I believe migrant workers played a large role in building this. Where did they live? Likely in employer provided housing. Yes. Proper sanitation? Likely no. Imagine the outcry using this cheap technique to build in Toronto.
..........WELL?