This is what I expected the cable guy to do. I don't think all of our cable channels are in HD. Many of them say HD, so they're obviously HD. I assume the ones that don't say HD are not HD, and they are the ones that are a bit blurry. Not sure what we can do to upgrade the viewing of those.Kirk is right, cable companies are constrained in bandwidth compared to satellite, and you will find fewer HD channels available on cable.
For example, in my area, DirecTV has 13 different channels of HBO, 9 of which are available in HD. Xfinity/Comcast offers 11 HBO channels, with only 4 in HD.
With more limited bandwidth, cable is forced to pick and choose which channels to offer in HD based on availability and popularity. That said, I'm surprised CNN isn't available in HD where you are, even if it's the Philippines.
The downside of having a high quality HD or 4K TV with a good picture is what you're experiencing. I have a friend who had a lower end Vizio 1080p TV years ago using Comcast, and you couldn't tell a lot of difference between the SD and HD versions of most channels.