Does it bother you that a typical search engine's shopping tab might as well be called the Amazon.com tab? Because it bothers me!
It is as if companies like GoogleYoutube are in league with Amazon.com and eBay. By the way -- I said "GoogleYoutube" to remind people that Google and Youtube are the same company.
Monopolies stink! Monopolies are rubbish.
If you want to help fight back against monopolies, then I suggest that you deliberately make the extra effort of searching for online retailers which are independent from the Amazon.com and eBay marketplaces.
Many Amazon.com and eBay sellers have their own websites, which can often be found quite easily by searching for the name of the sellers.
One of my passions is showing people that all of this is in the mind; that everything is a mental phenomenon. Seemingly small but well-meaning choices/actions can result in big ripples in the universal waveform, so to speak, improving how things are for everyone.
It is terrible for a small group of businesses to become as influential as some (democratic) nation states -- as even those companies described as having "gone public" do not invite everyone to vote on company policy. They only invite those who have purchased shares in the companies to vote on company policy, and very rich people can buy extra votes if they purchase lots of shares.
Don't let civilisation go backwards by lazily buying goods from Amazon.com and eBay, simply because Google is trying to push you into doing that. Don't stand by and do nothing when big companies like Amazon.com, eBay, and Google try to become as powerful as some nation states. Private companies are not genuine democracies. A lot of people complain about the USA, but at least it has a codified voting system of one vote per citizen -- unlike Google.
I want to make something clear, however: like with recycling or going vegan for the sake of the environment, every little helps. I don't want to cruelly shame people for using those websites that I dislike. If some of you choose to do what I have suggested in this thread every so often -- but not on each occasion that you shop online -- then thanks for that. Doing a little bit here and there to improve civilisation is better than doing nothing.
Despite what I have said above, I feel it is important to mention that supporting brick-and-mortar stores is even better than preferring independent online retailers over Amazon.com and eBay. One reason for this is that keeping high street shops open facilitates people doing their shopping without unnecessary fuel expenditure: something which is vital for protecting the environment. Walking to the shops is best -- but at least using public transport cuts down on the amount of harmful gas emissions per driver/passenger compared with driving to the shops by car. (Companies like Amazon.com employ lots of couriers driving around in vans.)
P.S. I hate eBay much less than I hate Amazon.com -- as eBay has not attempted to be both the online marketplace and the online store. I actually support Amazon's streaming video service as a competitor to Netflix though, since doing so serves my goal of breaking up worrying business monopolies.