That assumes a perfect, friction less economy. I'm going to make some assumptions here, but to hire a baggage handler you'll have to 1) pass a background check

That assumes a perfect, friction less economy. I'm going to make some assumptions here, but to hire a baggage handler you'll have to 1) pass a background check 2) Receive training on airport safety, 3) be trained on how to load and balance bags. That will likely to take 2-4 weeks, minimum. Additionally, Heathrow slots are already sold, they likely can't change the price for the next 2 months anyways. Finally, labor is a bit different then goods- if you raise the marginal cost of an orange all the oranges you've already bought don't suddenly start costing you more. If raise the wage to attract more workers you'll generally have to raise the wages of existing workers as well to retain them. This is a really bad situation if you have a lot of fixed price orders on the books (as Heathrow likely does with airlines). If you overshoot pay and hiring to fix a short term issue you can end up with a worse problem long term. Raising prices and pay solves the shortage in the long term, but in the short term it won't fix the problem, so the 2 month cap makes sense.