The mistake you are making there is assuming that those improvements add any value to the landlord or property. They don't. That $20,000 grease trap is an anchor that the next tenant has to have pulled out at great expense. They probably want different lighting so the electrical will have to be redone as well.
In any commercial property I have ever dealt with the tenant is responsible for any renovations because every tenant is looking to outfit the space differently. If the market is heavily in the favor of the renters at the time, I have seen landlords offer discounts on the rent to help cover certain renovations, typically expanded electrical service and the like, but even that has it's limits as landlords typically have costs associated with ownership they need to cover out of the rent.
Malls and (high cash flow) retail spaces will often provide tenants with money for renovations upon lease signing. For a 10 year lease on a proven business, it's not uncommon to have $20,000 - $100,000 build out on the space. This is, of course, priced into the lease.
In any commercial property I have ever dealt with the tenant is responsible for any renovations because every tenant is looking to outfit the space differently. If the market is heavily in the favor of the renters at the time, I have seen landlords offer discounts on the rent to help cover certain renovations, typically expanded electrical service and the like, but even that has it's limits as landlords typically have costs associated with ownership they need to cover out of the rent.