No that's not true, there is actually competition here and a very transparent market.
30 years ago when 2 Mbit/s was relatively new here, ADSL on existing phone lines had a price of 69,- €. (cheapest provider at the time)
Even without accounting for inflation, the price now is cheaper for 1 Gigabit, despite the old ADSL was based on existing cables! And 1 Gbit obviously is on fibre optic cables made specifically for internet connection.

The cost of establishing fiber networks was expensive, and it is only recently that some of the companies are turning decent profits, and I think most of the profit is on selling TV packs and extra services like cloud storage and virus protection. My internet bill has about 5 points of extra services that all have a nice round zero on them. 😋