There's a price tag associated with everything you mention. Where's the money to come from...
Clipped..
The Megachargers will have to be in place before the semis hit the road. That's a lot of infrastructure to establish in a matter of a couple years.
Money is ready to be had as long as it's expanding and growing the business. Tesla has had zero problems getting money. All those things you mention pay for themselves though they are but profit centers.
Megachargers may not need to be in place before. Tesla could set charging at facilities of companies purchasing the trucks. Commercial rates are already 7c before adding solar+battery. There is an issue with higher rates for spikes in usage, but I assume Tesla had a plan for that which includes solar+battery.
People also keep forgetting that there are a lot of incentives to build out solar+battery that goes above and beyond the savings in energy cost. Where I'm at, I earn credits that I can sell in an annual auction. This is for energy I create and consume. The amount is equivalent to about $150/MWh, paid out quarterly. Commercial rates are lower but still around $100/MWh.
One thing I know, Tesla has done their homework and I believe there is at least 30% margin in that 7c. It may be based on improvements to battery and solar tech that we have but been told about yet. In addition, the semi battery demand is basically a requirement of the gigafactory. Meaning, Tesla needs to make 150GWh/Y in GF1 to maximize the economies of scale. Without the semi, they can't even come close. The issues is that they won't be able to build 2M cars a year by 2020, so they need 100k semis to consume that excess capacity and maximize the economies of scale. Everything is cheaper when you buy 3x as much of it and you can make long term commitments to suppliers and those commitments are backed up by orders.
Tesla is about to become the largest utility and per generator on the planet. Nothing easier to get funding for then utility grade energy production and distribution where you have guaranteed demand. 500,000 cars and 100,000 semis would consume an enormous amount of energy and Tesla is uniquely positioned, even with home solar+battery, to supply all of it. You either don't get it or have not thought about it. This is what a paradigm shift looks like. The closest thing I've witnessed first hand is the smart phone. People went from no phones to flip phones in 2 decades then to smart phones and no landlines in 5 years.
If Elon says 7c then it's 7c. Now figure out why, not why not. Elon is often wrong on timing, but not the end result. This is what he meant about everyone understanding why they had to acquire Solar City.