Amazing. Let's truly take it from their point of view.
The only people who care about this plugin are HomeAssistant users, so a very small subset. Those users then either
A) Already own the product, and thus are not going to cost them anything because they already bought it or
B) Home Assistant users who are in the market for their product, and from experience will only buy a product if there's an HA plugin.
In what way are they losing "millions" to these 2 groups again?
I have literally made decisions on purchases like vehicles on if they have a home assistant plugin or not. For HomeAssitant users it's one of the largest factors.