They don't. For me, over the air cable fills most of the gap. The games I want to see that aren't locally broadcast send me to a sports bar.
In reality, I miss MNF. But most games I don't watch if my team ain't playing, so that maxes out to two games a year usually.
$8 (Hulu), $8 (Netflix), $8 (netflix disks) ,$0 (Crackle), = $24
Cable bill was usually at least $120 with the sports packages and HD.
Savings of $95 per month. So at the end of the year, I have $1140 that I didn't spend on TV channels that I don't use (or seldom use). Since I usually go to a sports bar every month or so anyway to watch a game that isn't local, that's a net savings of $1140.
For me, it's worth it. I don't watch $120 worth of broadcasting every month. When I watch TV, I can find the things I like on Hulu or Netflix without the need to pay for a BS DVR service fee of $6 a month, plus the cable bill itself. A minutes worth of commercials... big deal.