That is because nobody really wants ports at that speed. They are crap they are trying to sell to the home user market. Enterprise went to 10g ports and is now looking at even faster ports. At the time the 10g ports were too expensive but by the time these came to market the 10g ports had dropped in price.
Pretty much there is no market for them. You might as well just use 10g ports there is much more product on the market and many times it is actually cheaper.
There is also little purpose for any port above 1gbit in home use. Maybe a backup to a NAS might use it but you quickly hit hard drive performance limitations. Your machines have to be designed to transfer data at high rates. Pretty much anyone who needs this...