I mean De Lie and Philipsen don't have any problem scoring. Greipel cranked out like 10 straight 1000+ points seasons. So sprinters can score perfectly fine. They might not have the truly high end 3k ceiling of the best all around talents but how many of those guys are there really (let alone available at a reasonable price) ? Plus I could say the same thing of other specialists. You don't see pure TT or pure climbers types drop 2000 points season either.Sprinters generally dissapoint in this game, most points are in GC...
The problem is which sprinters people go after. For instance, is it really a disappointment when Ewan scores 500-800 points like he does every year of his career (bar an outlier in 2019) or is it people having unrealistic expectations ?
High end sprinters' performances are way more context and team dependent than other world class riders and it makes them much riskier gambles. Sure it helps if Pogacar has good teammates but even if he doesn't, he can just ride away from everybody else whenever there's a climb on the menu. Ganna can do his thing against the clock regardless of what else is going on at Ineos... A sprinter can be faster than all his competitors but he won't score consistently if he doesn't have a train to deliver him in the right spot consistently (or he is Robbie McEwen but he has been retired a while last I checked).
There's plenty of young, up and coming sprinters that are worthwhile picks every year though. Their progress tends to be more one huge jump and then a plateau versus the more gradual progress you see in GC contenders for instance. So if you time it right when they make that jump it can bring in a lot of profit.