Because there is a whole DualSense Controller connected to a 8" screen & SoC .
This make the money back through PS+ is backwards when people are already buying the Portal at $199 & the money from PS+ subs would not be pure profit so they would be giving up $50 upfront to people who may never use PS+ Premium or drop it after a few months.
Right now there is no reason that Portal should be sold at an lost , if they start selling people cloud versions of games like Switch & they actually sell well then maybe it would make sense to cut the price
In your mind you think Sony breaks even on Dual Sense controllers sold at 75 dollars? They routinely sell them on sale for like 50 dollars... They're making at the VERY least 35 dollars profit per controller sold if not more. They have a huge profit margin on the Portal just like they do on the Dual Sense Edge.
PS+ revenue, particularly PS+ premium revenue is probably the highest margin product sony sells. If even 10 percent of the people who purchase the Portal specifically because of a price drop get PS+ premium, it would easily offset the lost margin on the Portal itself but as I mentioned before also increases engagement on PS as opposed to someone buying a different device.
Anyways, not going to go back and forth with you on this.