Edit: This observation is only for US market in some hot real estate areas
They've previously bought up a large portion of the mobile home parks and rapidly raised the rents on people who usually have no options to move.
Also, comparing the zestimate for our house to what other homes are actually selling for are pretty comparable. I think what you're saying might be true for some markets, but I don't think it's deliberate. Zillow's been around for a while, and those Zestimates didn't used to be anywhere near as high as they jumped this past year.
Also, the Zestimates actually seemed to be a lagging indicator for last year, like they went up more slowly than the sold house prices (I was watching mine 2-3 times a month out of curiosity, although that's just one anecdote).
Locally, houses are selling on average about 10% over list.
Of the problems in housing prices, I really doubt Zillow is changing anything. Everyone knows the listing prices are garbage, and only work off closing price for comps. The issue is closing dates are 30-60 days behind the current market, which is a long time.
It's essentially impossible to know what a fair offer is today.
* It can be fun to revisit places you lived/stayed at and see what changed, if its been listed in the last decade. Kinda like a before/after on home improvement shows with your memory being the before.
In my past experience on HN this subject tends to become exceedingly emotional very quickly. Please do not reply to me about high economics with 0 data.
I live in the third fastest growing large city in the US. It has doubled in population over the past 20 years and may become one of the US 10 largest cities over the next decade. There is plenty of room to expand here with constant construction and no geographic or political boundaries. Property prices seem to increase proportionally to the increase of housing quantity as though increased quantity is fueling increased demand. Multi tenant properties only seem to pop up here once an area becomes to saturated with single family residences leaving higher density units as the only remaining option.
Despite there being very low financial barriers to becoming a home owner here it seems an incredibly high quantity of single family homes are rentals.
In many places you can offer the asking price and will be rejected as the seller is expecting more.