Why is it too simplistic. We're living in 2022 now, not 2020. It's not like the budget cap suddenly appeared. Everyone had plenty of time to adjust to it before it came into force. The blunt truth is that some teams did not want to adjust or were worried that their direct rivals would not adjust and so chose not to adjust themselves.
Because you’re comparing Williams with the top teams. A team which is used to run its organization for a budget of 110m and teams who are running an organization based on a budget of over 400m.
Williams doesn’t have to adapt to the budget cap, the top teams do and that isn’t a easy task considering what they used to spend.
They are probably all on the limit of what can be spent within the budget cap and inflation made it even worse.
Maybe the could save on their development budget, but that is probably about 7-10% of their total budget, if we can believe the estimates of the media, and that won’t be enough considering the inflation rates they have to deal with.
Travel, staff costs, energy, telecom, engine fees, property costs, materials to build the cars are all pretty much fixed costs where savings aren’t possible during a season. In fact much of those costs (f.e. energy, traveling and materials) increased during the season.