In all honesty, at the prices quoted, it's probably both. First and foremost the businesses need to be making very healthy profits to spend £40k on an exec box. When you look at the demographic of the box holders currently, it's small(ish) independent local businesses that have SWFC fans as owners. It's already been alluded to, but I'd be amazed if many box holders actually use it for entertaining clients, as there's very little appetite for it. There's a number of boxes where they're made up of individuals buying a seat each, but again at circa £4k per seat, it's a very expensive hobby.
Your point on service/offering obviously helps to make it more appealing and offsets part of that. Ultimately, it will always be an expensive way to watch football, but allowances are made if the offering is deemed worthwhile. I think the corporate world will be similar to your average fan, who considers the price increase to be a significant 'buy in' to the Chansiri era - it'd be much easier to swallow having just signed Rhodes & Wickham for example.
There's such a long way to go in terms of service matching the price paid, that it's a big leap of faith required for people to anticipate such a large improvement overnight. The staff serving are very young, with no real customer service experience. They're often covering multiple boxes and that has a detrimental impact on the service that can be provided. Often menu choices run out, waitresses leave at half time and I can only see it getting worse if people begin to eat in their boxes, as it will live or die by how attentive the hosting skills are.
Given the number of boxes that remained empty thoughout the previous season(s) and the number of living social etc deals required to attempt to fill them, I can't help but feel that the equilibrium has been miscalculated here.