However, government funding is low risk/high return for the companies that actually receive the funding.
I completely disagree. If this were true, Lockheed Martin, BAE, Northrop Grumman,
etc. would be the most profitable companies around, instead of Apple. Government contracting generally means accepting a limited profit margin, dictated by the government, plus a shitload of overhead to make sure the contractor is meeting the terms of the contract and that everything is accounted for. The reason government contractors do it is because it's low risk and decent return, not high return. It's almost a sure thing basically. Once your company is big enough and established enough in the government contracting space, you just have to keep doing what you've been doing and reliably provide service and you'll get more contracts and have a continuous source of revenue, though it is subject to political dealings and changes. But if you have a multi-year contract in place, you can count on getting continuous revenue for that time, as long as you live up to the contract.
By contrast, a company like Apple can make huge profits by selling overpriced Chinese-made stuff to gullible consumers, but only as long as their marketing convinces them it's fashionable. As soon as consumers, who are known to be fickle, decide something else is more fashionable, or Apple pisses them off somehow, the house of cards can collapse and their profitability disappear. The risk is quite a bit higher for companies which sell directly to consumers, but the potential for profitability is higher.
there is going to be little return from that because there is nothing on Mars that we want or need right now.
There may be mineral resources there. However it's ridiculously far away and it's unknown if it does have any significantly valuable resources. What makes a LOT more sense is near-earth asteroid mining. There's already some billionaires who've set up some venture to work on that. It's quite likely there's very highly concentrated ores in asteroids which pass relatively close to Earth, of very valuable materials like platinum. We already know how to launch probes to stuff within the orbit of the Moon or so (or really, all the way to Pluto), and with anything as close as the Moon, you can even remote-control it in almost realtime (a few seconds' delay), unlike with Mars where you need to wait 30-60 minutes to hear back from your rover.