While similar I don't think sambal oelek and sriracha are the same. Sambal oelek is typically pretty chunky, sriracha is usually very smooth. Sambal oelek will be pretty much just vinegar, salt, and peppers while sriracha will be sweeter and have garlic.
In urban areas its not necessarily too hard to find a variety of both. Going further out it'll get harder, so the brand presence of sriracha will often win for the spot of the sole Asian-style spicy sauce on the store shelf. Asian restaurants will typically have one or the other. I think a lot of Americans prefer sriracha partially because of the brand presence but also because of its smoother texture. Americans have tended to use a squeeze bottle for condiments more, having a jar to spoon things out just isn't quite as popular. Even things like relish, jelly, and sour cream these days are moving towards squeeze packages instead of jars and tubs.
In urban areas its not necessarily too hard to find a variety of both. Going further out it'll get harder, so the brand presence of sriracha will often win for the spot of the sole Asian-style spicy sauce on the store shelf. Asian restaurants will typically have one or the other. I think a lot of Americans prefer sriracha partially because of the brand presence but also because of its smoother texture. Americans have tended to use a squeeze bottle for condiments more, having a jar to spoon things out just isn't quite as popular. Even things like relish, jelly, and sour cream these days are moving towards squeeze packages instead of jars and tubs.