This is close to how the TARP bailout (2008) worked and the government did get the public's money back. From the banks, the Treasury got about a 21% profit (https://www.thebalance.com/tarp-bailout-program-3305895)

One thing to remember is that the current share price of companies is based on the value that buyers and sellers are agreeing to. There are many more people who own shares and are unwilling to sell at the current price. When someone talks about Boeing costing $51B, that doesn't take into consideration that many people holding Boeing shares wouldn't sell at that price. That's the price you can buy at if you're looking to buy 1 share. If you're looking to buy all the shares (or a substantial portion), there probably aren't enough sellers at that price.

The point of that is to note that companies will reject money that comes with terms or pricing that is too bad. If you offered to give Boeing $60B in exchange for 100% of the company, shareholders would reject it. Might as well take your chances that the company will survive. Fire all employees, eliminate all payroll for a year, and then try and re-start in 2021. If you ask too much, investors have other options.

For the government, these other options are really bad for the economy - and ultimately for government revenue. We don't want a situation like that if there's a way to avoid it. If the government lends $10B to a company at 0% interest and it means that the company keeps paying $5B per year in taxes instead of filing for bankruptcy and paying $0 in taxes, that's still important even though the government is getting no interest. One thing that people don't realize is that the government basically already owns parts of companies - the government gets a percentage of the profits. If those profits go down, so does government revenue.

The TARP bailout was smart. Dividends to the government were between 5% and 9% interest along with warrants for shares. Usually banks bought the warrants back from the government rather than the government converting them into shares and selling the shares, but it's essentially the same as what you're talking about (without throwing the market into chaos as the government tries to find buyers for hundreds of billions in shares).

Could the government have gotten more? Maybe. Berkshire Hathaway got a couple deals at a slightly higher interest rate before the government started stepping in. However, some banks wanted to reject the government's help because it was expensive - they thought they had enough reserves to weather the storm without help.

It's bad that the public thinks of these "bailouts" as free money. They aren't free money. It makes a lot of sense for the government to be a lender in a time of crisis since they're the only lender that can print money. If the government lends with an appropriate eye to risk and sets reasonable interest rates and secures those loans against the companies, it's a really good thing for the economy.

Personally, I think that the government should also be working on the individual side as well. In some ways, they are. Unemployment usually covers instances where you're temporarily unemployed for things like this. I'd go even further and say that the government should save money for rainy days and give people grants (rather than loans) to keep everything normal. Bailout loans wouldn't help a lot of people who wouldn't be able to pay back an 8% loan easily. However, grants would go a long way to making sure that people were taken care of.

If people start spending less money, it has cascading effect. Businesses employ X number of people assuming a certain number of customers. If their customers go down by 10%, they probably need 10% fewer employees. Then those laid off employees start spending less causing other businesses to lay off unneeded employees. Then those new laid off employees spend less causing... and so on.

We want the country to go through this crisis as smoothly as possible. The government should lend money to companies on terms that are good for the government and good enough for companies that they'll take it. We don't want companies thinking that they should take their chances or shut down for extended periods of time beyond what is necessary for public health. We don't want a huge drop off in government revenue if companies shut down more than is necessary for public health.