I don't know the exact numbers but the cost target is certainly not 100 USD, especially if the target retail price is under $60 ;)
To get some idea the LCD costs on the order of $4, and the MCU $1.5. Any cost increase over $1 requires extensive justification and (most likely) shaving costs elsewhere. A bigger display compounds the cost increase because the PCB also has to be bigger (+$3), the MCU has to be in a bigger package (+$1.5), and of course the LCD itself is a bit more expensive (+$2). In total that is $7.5 of additions which realistically means +$22.5 in retail price, which make a huge difference in competitiveness of the product. To get an idea compare the sell volume of the NanoVNA-H (4000 units/month) to the NanoVNA-F (100 units/month).
OwO