The majority of problems with the Hyperloop are related to land acquisition, developing practical fail-safe solutions, establishing appropriate insurance, promoting user acceptance, and balancing return on investment. The first few examples will likely end up slower than originally hoped and too expensive to break even, but my guess is that they'll figure it out eventually.
Being a long-time end-user of computer hardware and software products, I do not think that anyone will develop "practical fail-safe solutions" to ensure safety while riding at 700 mph in a pod running in a vacuum. And even with well-developed technology, like airplanes, we still have some pretty spectacular crashes - Boeing 737 MAX, anyone? Well, at least with a major hyperloop crash, they'll be able to recover most of the bodies....
The environmental harm that comes from lithium ion batteries is a genuine problem but it is also vastly overstated when the total chain of production to exhaustion is compared with more conventional solutions. Electric cars barely use their brake pads and low resistance tires last longer than conventional designs.
Uh, oh, you're getting into something I know something about. The early versions of low rolling resistance tires did, in fact wear down more quickly than conventional tires. In fact, when we first started trying to encourage truckers to use them, they complained that the tires wore out so quickly that it negated the money from the fuel savings. The major tire companies soon came up with low rolling resistance models that didn't wear out as fast, but they're no better than conventional tires, so the particulates from tire wear are going to be more or less the same either way. Except that they companies that make low rolling resistance tires with good wear performance are the top tier companies (like Michelin, Goodyear, Bridgestone, etc.), and those good tires are more expensive than regular tires. So anyone on a tight budget is going to either be buying conventional tires or low cost knockoff off-brand low rolling resistance tires that will wear out faster. Thus particulates from tires in the electric world will either be the same or slightly more than from conventional tires.
Traffic doesn't go away when cars become electric, but it can be mitigated by removing the human element.
Again, being a long -term user of computer hardware and software, I have no confidence that full automated driving on public roads can be done safely and reliably.
Relying on individual transportation has many other problems besides traffic. Daybeers pointed out issues regarding land consumption,i.e., urban sprawl. Having everyone own a vehicle ties up a lot of metal and plastic that could be left in the ground. Urban sprawl has a lot of environmental issues aside from greenhouse gas generation, such as promoting flooding and interfering with ground-water recharge due to vastly increased paved surfaces and low density housing. It's also associated with other sorts of low-grade toxic runoff, and, of course, destroys ecosystems, many of which provide "services" to human communities. (Wetlands absorb floodwaters, and recycle fertilizers, etc.)
It's probably true that the most environmentally friendly way to have any kind of high-tech society is to minimize the "human habitat" with dense, walkable cities for the vast majority of the population, connected by high-capacity transportation modes, i.e., public transportation. If that means that poor ol' Elon Musk is going to have to live in an apartment or row house and have to walk a couple of blocks to a bus stop of subway station, and then have to wait a few minutes to ride with the riff-raff, well tough luck. If he's serious about helping the environment, that's what he, and everybody else, for the most part, is going to have to do. Maybe the really small percentage of people who really have to live in the sticks will be able to have cars, and perhaps it won't hurt to much to allow city dwellers to rent cars for road trips into the countryside for vacations and such, but if we're really serious about protecting the earth, most of us are going to have to put up with not having individualized instant mobility (except for walking) at our fingertips. In some ways, if we try it, we'll probably be happier people. We'll certainly be healthier from all the walking.[