The land valuation model certainly has some merits; in the end real estate values certainly have more to do with the land than the structures on that land. If everyone bought just the land, demolished the house and built from scratch, then I think this would be a more pragmatic approach.
I dont think Realtors are going anywhere anytime soon, and see significant value that we can bring to clients. Transacting real estate can be a stressful & emotional experience for many people; they want support & guidance, and to know that someone is looking out for their best interests. I know of many scenarios where consumers purchased or sold without a Realtor, only to regret it later. As much as some people dont like that Realtor's charge fees, there is nothing preventing FSBO's, Comfree's or sneaky investors from pulling the wool over a buyer's eyes to complete a sale to their perosnal advantage. Similarly, I know of some investor's who managed to convince a seller to let go of a property way below market value, just so that they could turn it around for a 6 figure profit. How is that fair for sellers? There are many scenarios where a Realtor is well worth their fee for sellers or buyers.
When comparing 2 pieces of land in the same area, its helpful to gauge how much better/worse a property is compared to the 'average'.
If resale values were based just on land values, then where's the appeal in upgrading or repairing your home before selling? Why would someone flip a property? How would one valuate 'move in ready' vs a 'fixer-upper' when looking only at the $$/ft2 of land?
There needs to be a way to account for the costs of say granite vs laminate counters, or new windows & shingles vs original items, or a cracked leaky foundation versus a solid foundation with weeping tile & a sump pump. There's the cost of the work, the time & effort to get it done, and a premium to be paid for making that property exactly what a buyer is looking for. There will always be an emotional component of a property transacion. There will always be reasons one wants to buy in a given area, or why they prefer a certain style of home, upgrades & features. And tThere will always be a reason that a seller wants to sell.
In some provinces the MLS data is already public knowledge. In AB they have been talking about it. MLS data isn't public info yet, but finding out what a house sold for is quite easy to do as land titles is public information. For $10/title you can find out who owns the property, and what the "consideration" was when they bought.
I think that companies like OpenDoor or Zillow are likely to make good $$ in the near future. Rather than Realtor's making money, it'll be the software developers or programmers, whomever figures out the platform that works. In the modern world, people want to do as much as they can for as cheap as they can using online tools. I know these platforms will start to shift some business away from Realtors> also see it as an opportunity to work harder to earn business and add value for those who choose to work with a Realtor.