Most things that can be exactly quantified by you, can also be figured out by your competitors. It's intangible assests, i.e., brand recognition, leadership, market penetration, customer relationship, all of which can be realistically increased by IS initiative, that make business growing. Practically, intangible benefits can be still translated into forecasted sale increase, forecasted revenue increase, forecasted productivity increase, forcasted cost decrease and so on. The sole success of this forecast or justification is knowledge in its own market and its own operations. In a capitalistic market, investors value a company by its market capitalization, tangible asset plus intangible asset.
Investors have their own rational expectations about intangible assets.
Only over the long term can company's market cap be proved and if it failed the proof, the market will correct its market value.