I would agree with this as they would be extremely popular, however I prefer racing online with the slower, older F1cars - my favourite from PC2 being the Lotus 25. I would add its 12 cylinder competitors the Ferrari 1512 and the 1965 Mexico GP winning Honda RA272.
I had to buy Assetto Corsa to get a front engine F1 car (that game has two different 2.5 litre Maserati 250F's). Project Cars for me needs at least one front engine F1 car. They don't have a Maserati license so how about a 1952/3 Ferrari 500 F2. In those years the World Championship was run to F2 regulations due to a shortage of F1 cars (Alfa Romeo having retired and BRM not being ready). The 2 litre 4 cylinder Ferrari 500 won almost every world championship race in two seasons and gave Alberto Ascari 9 consecutive wins.