How many nodes is too many? Has anyone done the math on this?

For example, if we had 10’s of millions of nodes all connecting to 8 peers would there be some latency issues in propagating blocks across the network in the 10 minute block intervals?
The probability that 1 node is connected to another node will be 1 in 8, so if there were 10 million nodes, we can divide it in 8 block of nodes, every node will have access to one of the blocks.

The transaction takes less than 1 second to transfer from one node to the other, let suppose it takes 1 second, to make it easier.

On first second 8 nodes will be notified
On second 2, 8*8 = 64 nodes will be notified
On second 3, 8*8*8 = 512 nodes
Continuing this way, 8 seconds after the block is issued, a total amount of 16 million nodes can be notified of that transaction

So there is no problem with 10 minutes block, the problem arises when the block is for low times, like on some chains with 1 minute per block or less.