It's a price and usability problem. The basic functionality (SSL Client Certificates) is built in to all major browsers and servers. Enabling it up takes only

It's a price and usability problem. The basic functionality (SSL Client Certificates) is built in to all major browsers and servers. Enabling it up takes only a few hours and doesn't require any third-party software or hardware at all. Actually getting your users to buy a smart card reader, find a card that has drivers for their browser/OS combination, buy that card, and spend half an hour setting it all up? Good luck with that.