If I save a svg to a html5 canvas and then make a css to resize the canvas I get a blured image.

<style>
    #canvas
    {
    border: 3px solid green;
    background-color: lightblue;
    width: 800px;
    hight: 600px;
    }
</style>

<canvas id='canvas'></canvas>

Once you export in html5 canvas it is not anymore an SVG file, it is a raster object drawn by javascript into the canvas object. Blurring may depend by many factors like CSS rules missing or by your browser setup, etc...