QUESTIONS, NOW WHAT IS GOING TO HAPPEN

i just whatched the endo of season 3 episode 22 and it said " TO BE CONTINUED ". HOW COME THERE'S NO EPISODE 23 OR SO THEY CAN CONTINUE WITH THE SHOW. I LOVE THIS SHOW, THEY SHOULD HAVE MADE MORE SEASONS, LIKE SEASONS 4,5,6 AT LEAST OR 4 & 5 CAUSE NED MALONE DIDN'T COME BACK AND ALSO ARTHUR SUMMERLEE. Y CAN'T THEY EVER CONTINUE WITH THESE SHOWS.