$250 doesn't get you a lot in a receiver. I never spend less than $500 on a receiver and it has to be a Marantz or Denon.
It does if you know when and where to make your purchase. At the right time of year with the right vendor you can get receivers for close to half the full price. It gets even better if you look for deals on last year's models. Receivers can be had at discount prices much easier than sound cards can because it's such a bigger market.
It also depends quite a lot on what brands you shop for on anything that retails for $600 or less. In that price range Pioneer rules on sound quality. They're also 2nd best to Yamaha on reliability.
As for Denon and Marantz, they're both owned and made by the same company and Denon has been in financial trouble since some of their higher end retail vendors dropped business with them.
Denon went on a binge to offer low priced models and sell all their product at numerous vendors, including some online ones that were undercutting prices of retail stores drastically, which is what caused some retail vendors to stop doing biz with them.
Another thing that is hurting Denon is they've made their product in such a way that it heats up too easily and causes parts to burn out. I've encountered numerous complaints about this and the support afterwards, esp now that Denon is hurting, is not so good.
There are actually guys in the biz of buying used Denons for cheap, installing several fans inside them, and making a slight profit off them with no warranty because Denon has such a huge fanbase despite the problems they've had. IMO that just makes it obvious they're poorly designed.
Onkyo used to have such problems, but they've redesigned their latest models to run much cooler, but then I've also noticed Onkyo no longer has any models under $850 with MultEQ like they used to. Likely a tradeoff of affording the retooling. I doubt Denon could even afford such a retooling at this point, and the sad thing is, they may bring Marantz down with them if things don't improve.
The fact is if you pay upwards $600 or more, a lot of receivers sound good, esp if you buy $1000+ units on sale for that price. Even Best Buy Magnolia has closed out Yamaha RX-A1010s for $600. I don't think most gamers are going to want to spend $600 or more on a receiver though, and it's just not necessary. I've heard first hand what a drastic improvement even sub $300 receivers can yield over even decent sound cards.
One thing a lot of people seem fooled by is thinking that a $250+ sound card is going to give you the fullest quality of sound it's capable of, but the PC speakers most use with them bring the sound quality back down due to their cheaply made amps. There's also not even enough room on a sound card to use the components necessary to really give you full sound.