Because let's be honest if there's no rules for the car, and you can just keep throwing money and different tech from multiple types of race car then of course the car will catch and over take the bikes in the end.
That is my only point. Take all rules off the table, the car will be significantly quicker and certainly quicker than the fastest bike today. We can debate all you want, in 3-4 years time I suspect you'll see that exactly happen. You are talking fractions for bikes to get quicker, cars have a long way to go yet.