I understand that is the point but it is not viable on a mass consumption level. Mining it is too difficult and its only going to get harder. There are already issues with supply shortages with gpus(before the microchip shortage) and energy issues. This will only increase as the price for bitcoin continues to climb which I think it will. It will have some crashes and rebounds but the price will probably always go up in the long run.
Imagine what happens in 30 years when there are no more coins to mine and a few handful of whales pass away without giving some one else access to their wallet. The coins will be lost. Imagine this happens for another 30 years and slowly the supply completely disappears. The people holding bitcoin will probably have massive demand for their coins if the world hasn't moved on to something else.
There needs to be another mainstream coin to take bitcoins place. This blockchain needs a unique burn rate and an ability to resupply the coins in a manner that helps combat inflation..... spit balling here..... maybe another few million every 10 years or something.
Or maybe the answer is not a unifying coin that does it all but an underlying tech that lets all blokchains communicate with each other. That is what polkdot is trying to build.
1. GPU's aren't used to mine BTC. ASIC's are. GPU's are mainly used in altcoins, like ETH.
2. The energy usage with BTC is interesting. On one hand it helps make it more secure. I've seen arguments that it subsidizes renewables, or uses unused energy, etc. I think in the end it will have a way of solving itself out.
3. The last BTC won't be mined until the year 2140 I believe.
4. If a whale dies and loses the coins so what? Ships around the world sank all the time losing fortunes of gold. People didn't stop using gold.
5. Bitcoin combats inflation, I think you are conflating it with Deflation. Which in my mind isn't a bad thing when it comes to a store of value. I hold BTC because I know in 5 years I can purchase more with said BTC than I can then if I stuffed the equivalent amount of dollar in a mattress for five year.
Your last point is fine, there are many coins that already attempt to do that on the ETH ERC20 token stuff. BTC is a way to remove control of money from the Banks and Government. It's not meant to solve any other problems. It gives the power to the people. It's can't be stopped, hacked, or inflated.
All other issues can be solved by other blockchain tech.
Blockchain can solve any issue where you have to trust a third party. Be it another person, entity, corporation or government.
Blockchain can bring about fair, accountable elections and are publicly auditable. There are so many useful things it can and will solve in the future.