People say this every single year. Sometimes it happens, sometimes it doesn't.
The most common line was 4.5 QBs in the first round at any point, albeit with the UNDER being better odds. Last year's draft's line was also 4.5, just weighted differently. But the line assumed that Hendon Hooker was the swing. Levis wasn't even in question. QBs get pushed up draft boards, but they also get talked up in draft media. I'm all for pointing out that draft betting is a soft market, but this particular aspect is not the easiest thing to parse.