A Rant and Question about cookies

Today I was locked out of a site I've been using for almost a year because they require cookies, they never required cookies in the past. No cookies, no access. I know why cookies were developed and I appreciate how they're being used these days. My question is this: Now as I understand cookies, there can only be so many cookies in the cookie jar...before other cookies are deleted or over-written. You can't have an infinite number of cookies on your hard drive and with everyone issuing cookies and some places now requiring cookies....doesn't it all become a little self-defeating....cookies I mean. Or am I missing the concept of cookies and how they work. ken