Beg your pardon? Before SpaceX came along, their cost was fairly competitive, and they had over 80 consecutive successful launches. It's not been quite as reliable as the Ariane 4, but still has a success rate of over 95% (93% if you discount partial successes), so it's not exactly a dud.

But yes, it's not as competitive as it used to be, and a successor is overdue. Funny to read Ariane 7 is being planned before 6 has even launched the first time.

Edit: Just to illustrate the reliability point: JWST was launched on Ariane, partly because it was such a proven, established platform with a good track record.