First of all, welcome!
1) Once all 21million bitcoin have been mined, will transaction fees be enough incentive for miners to continue validating transactions on the blockchain?
Currently, each block rewards 6.25 BTC plus a little bit more than 0.1 BTC on average in fees. So, when the block reward becomes less than 0.1 BTC (not necessarily 0 BTC), I suspect that there'll be miners.
As for the incentive, if at the moment 1 BTC = $47,000, then their reward is ~6.35 BTC = ~$300,000k. In order for them to have the same incentive when the block subsidy reduces by a lot, then 0.1 BTC has to cost $300,000 which makes 1 BTC valuated at $3,000,000. (ceteris paribus)
2) What is the significance of bitcoin being "open source"? Doesn't that mean that the fixed amount of Bitcoin in the original code could be changed? (This speaks to my lack of programming knowledge I guess)
They can be changed, but the change will only affect your node. Bitcoin is community-based. There's no entity that dictates what to do with it. So, in order to achieve increasing the 21 million cap, you have to convince the overwhelming majority do so, otherwise you're just running an altcoin no one agrees.
3) A major draw to cryptos like Bitcoin is its decentralized nature. But in order to participate in the game, you need an internet connection right? So aren't cryptos unavailable unless you have a centralized power that provides the ability to connect to the internet? (Maybe this speaks to a lack of understanding about how the internet/wifi connections work)
And so as to sustain your food, electricity is required. Does that make electric power industries almighties?
4) If a block is limited to approximately 2,400 transactions. Once Bitcoin becomes more widely used and there are millions of transactions taking place everyday, wouldn't that create a backlog of transactions? And couldn't that make the system super slow and inefficient at confirming transactions. (could the code be updated to allow blocks to be confirmed faster than 10 minutes?)
The problem you describe is called the “
scalability problem”. A short answer is that we're working on off-chain solutions such as the
Lightning Network to tackle it. If you increase the block size (to allow more transactions to be included) you're making more expensive for the average user to run a node, which brings discouragement.
It also isn't a practical and efficient way to encounter this issue. If you want to learn more about it, I recommend to create another thread dedicated to it.
I've heard it said that world powers typically last for about 250 years. As the United States is coming up on its 250 year anniversary, could failure to adapt to cryptocurrencies, overregulation by government that slows progress, etc. be our downfall as the rest of the world speeds ahead into this new world and we are left behind?
Who's the rest of the world that speeds ahead and who are we who don't?