Steinberg has announced that they are developing a new licensing system that will allow all their products to run without a dongle. There is no timeframe for this at present, though.
When you upgraded WaveLab to WaveLab Pro, you gave up your WaveLab Elements licence in exchange for a WaveLab Pro licence. WaveLab Pro licences must live on a USB eLicenser under the current licensing system (WaveLab Elements licences can live on a soft eLicenser or a USB eLicenser). This means the only way you can run WaveLab with your current licence is to have the dongle plugged in.
I have a similar problem to you. My USB eLicenser has Nuendo 11 and WaveLab Pro 10 licences, so I cannot use two major applications without my dongle.
Does Steinberg’s Zero Downtime help? If your licence(s) are registered in My Steinberg, and you lose a USB eLicenser or have it stolen, you can get an immediate temporary licence and replacement permanent licence shortly afterwards. Ideally, you need to buy a spare USB eLicenser so that you have a replacement ready to set up if you ever have to make a Zero Downtime claim.