Micro transactions were a thing during the early years of Bitcoin, but within time they have disappeared, at same time gambling got extremely popular. What I understand from this is that people aren't interested in micro transactions anymore. They want to earn more, in larger sums, so they have raised gambling to a level where it has almost became a monopoly inside crypto industry, while other categories of services lost importance and adoption.
One of the main segments of micro transactions inside Bitcoin environment were faucets and micro tasks platforms. However, without enough sponsor from ads companies and limited offers available for third world countries, users really went for another methods, with the promise of making superior profit. That is where gambling stands out.
This is a good recap of the story. Micro transactions were popular in early years because there were a few transactions in the mempool and you could get away with 0 transaction fees. If blocks are full today, they were empty years ago and it was making Bitcoin transactions extremely cheap, it was also making Bitcoin micro transactions possible. Also, at the same time, Bitcoin's price was significantly cheaper. If today you pay $0.16 on an average transaction, when the price of the coin was $1000, that fee was $0,0016. As the price of the coin goes up, transactions also become more expensive.