To the lay person it must feel like GWR▸ simply don't want their custom (which tbh, if the situation with short formed services and cancelations continues much longer, that may well be the case!).
Custom is already being lost - not a question of "if it continues much longer", I'm afraid.
And the traffic that's being lost won't spring back as if there had never been a problem as and when the issues are fixed. Each train that's so short formed that people can't comfortably get on, and each train cancelled on the day it's supposed to run and is in people's plans, looses goodwill and custom not only in that train but for their future train journeys too.
First (Great Western Railway) do want the farebox income from passengers - they do want the custom - during the current franchise,
where it is profitable. You could argue that where a service cannot run, cannot take everyone, or fails to make an advertised connection, the accountants would prefer people not to travel by train or rather by that train replacement, as it typically costs more to provide than the income generated; having them travel at another time / another day would be better for the balance sheet, should they travel at all.
Building business for the time beyond the current franchise is much muddier water. If the state of the system and passenger base is significantly lower at the time of bidding for the next seven or so years, then bids will most likely be lower and the long term financial effects from that will be born not by the next operator, but by the public. That may be in the form of general taxation (via the less positive franchise payment effecting the
UK▸ economy), it may be in the form of fare and other ancillary payments such as car parking charges, and it may be in the form of offering a cheaper to run lesser service in the franchise.
At times, we tend to look at (and make decisions) based on direction and rate of change, rather than on current performance. So rate of change from a very low base back to(wards) where it should be will, I expect, be a major element - and a positive one - as the current incumbents bid for the next franchise. The cynic would suggest than a poor autumn in 2017 followed by an excellent recovery from that though 2018 could be "just what the doctor ordered", especially with so much of the blame for current problems being directly and indirectly attributable to the slippage of electrification, and with it slippage of new stock and cascades. Of course, that does rely on an excellent recovery, or at least signs of one, in the not too distant future now ...