It’s basically the minimum amount of ETH needed to ensure there are a lot of validators all in sync. If it was less than 32 ETH, there would be way more validators and it would be very difficult for them to all sync to the correct block every 12 seconds.
Originally it was 3200 eth, but the price has risen too much.
Not exactly. The main reason they reduced it to 32 ETH was because of BLS signatures, so a lot more validators could be in sync with each other
But yeah, 32 ETH at the time of the Beacon chain starting was only a few thousand dollars