There's nothing illegal about creating a public company, no matter how stupid it is, if your finances are above broad. Financially, SPACs are as simple as a public company gets: practically take people's money and hold them in a big pot.
There's also nothing illegal about a public company acquiring or merging with a private one, although I believe this is the Achilles' heel of our current legal system: mergers generally don't require the same level of minute disclosures an IPO does.
Clearly, this is a regulatory arbitrage, just like a lot of our "innovations" in the past decade, fueled by a near zero interest rate. The way to move forward would be to take another look at our regulation and close the arbitrage. Otherwise, next time there's a low interest rate environment, I can guarantee you there will be another garbage SPAC boom.