The knock-on effect to other suppliers is also huge. With BA retiring some 30 or so 744's that is 120+ RR RB211s no longer need regular support and spares etc. With the rumoured 20+ 777s maybe going too, this could be another tranche of RR engines too (dependent of course on whether they are GE or RR frames being retired).
Fortunately RR have a military engines, industrial division and a nuclear propulsion arm too but the Civil Aerospace division is by far the largest.
Don't think RR will suffer too much, they have a near monopoly on the A330, and a monopoly on the A350.