I won't fly with one of the low service airlines now because the difference between the cost of a "low service" ticket and the normal airlines is not great enough to cover the hassle factor.
Is suspect A and C, that you are in the minority on this.
Yes Legacy carriers will look to save costs, just as Lower Cost carriers will do the same.
Don't forget that many many legacy carriers are crippled by restrictive labour practices, high administrative costs, and the commercial pressure to maintain frequency on certain routes that offer poor yields..
Lower cost carriers have typically more ability to be flexible, innovative, and adaptable. Certainly many of the marginal carriers will fall by the wayside, but I would argue that Lower cost operators will feel less pain in the current environment as many potential customers search for the best value proposition in the marketplace.....and that for many customers is not a legacy carrier.