Because owning a piece of property and charging for it is just extracting value out of something static. If investing in a company building or producing something you're helping create value.
Yes, the property has to be maintained, but generally the cost and effort of doing that is minimal, and the usual things that break need to be fixed by the person living there, not the landlord.
I think you might be comparing apples and oranges when comparing investing in a company and investing in real estate. There are different ways to invest in a company and different ways to invest in real estate.
Investing in a company to help fuel its growth, like VCs do, is analogous to investing in a new development project. There are lots of firms that provide equity investment to developers for new construction. Much like VCs these firms are interested in helping to create something new to meet market demands. Also like VCs they are typically looking for an exit event, where they benefit from the sale of the recently developed property.
The tech analogue for being a landlord - holding on to a stable asset and maintaining it - is holding on to an already profitable business and just maintaining it. For example, there are lots of SaaS businesses that have a decent number of customers and the owners are happy to just do the minimum needed to maintain the code and handle customer service requests. You can buy and sell these businesses as an investor much like income-oriented real estate investors buy and sell fully-leased apartment and office buildings. These investors are not helping to create something new in a direct way.
However, those income-oriented investors do create a market for stable assets, be it a Midtown Manhattan office building or shares of GE. They aren't directly investing in growth, but they are providing the incentive for growth. After all, while an early stage growth investor might be happy to know that they can sell their stake to another growth investor, as a company gets bigger and bigger its room for growth tends to diminish, and growth investors become less interested in buying it. But the market for its shares doesn't disappear. That's because there are investors looking for stable cash flow, even if it's from a static asset - be it an apartment building from the 1970s or Oracle.
It is not something that I feel or believe, it is factual. I know this because I am both a renter and a landlord. I inherited a property which I am now renting out, and except for a few major fixes, I have left the property pretty much as is while collecting quite a bit in rent from the occupiers.
In the same vein I could just purchase a property and rent it out, in doing so I have not created it - it already existed - but now I am just extracting value from it. Same as the bank will do to me with the mortgage.
For houses this is not the case. You actually have to produce houses and you have to constantly work on them so they don't collapse after some time.