cryogenics are largely off the shelf commercial things. For half a million you can have a dil fridge delivered to your house. There's also lots of room to make them cheaper. A few lasers (where a neutral atom system needs many) can easily total to half a million. Having worked on superconducting quantum computers and now on neutral atoms, I now am a bigger fan of neutral atoms, but I do find that people outside the fields get hung up on what don't seem like the difficult parts to me.