Here is an example:
Three hosts, each running two Windows Server VMs, each with two sockets. Say Dell Power Edge R610 or HP Proliant DL360 nodes. Windows Standard Licensing.
Cost per license: ~$700
To license each node to run its normal load is $700 for a total of $2,100.
If we want to address the ability of any node to be a failover for the others or for non-disruptive maintenance, we need an additional license per machine. So we suddenly jump from $700 per node to $1,400 per node and the whole cluster jumps to $4,200 while gaining nothing during normal production times.
Now that only addresses single node failover. If we want to maintain the ability to do failover during times of maintenance we need yet another license for each machine! That means $2,100 per machine and $6,300 for the cluster.
Suddenly $350 per virtual machine in licensing has exploded to $1,050. A non-trivial increase.
Now we can choose which level and which features we want, but typically the value of an inverted pyramid is sold based on this top level of flexibility. If we are dealing with Data Center licensing this is more obvious and far less complex, but SMBs would rarely pay for that level of workload and may not think through the additional costs that this style of architecture potentially bring to the table.
