That's one perspective. But let's look at the Sahel, the region just south of the Sahara. It is a very arid environment with thin topsoil, but that still maintains plant and animal life.
Humans have inhabited this region for thousands of years. Before European involvement, there were 2 groups of people: Herders and Farmers. The farmers were very spaced out, due to very thin and fragile topsoil. Since the nutrients were so scarce in the soil, they had developed a system over time of rotating crops every year so that each bit of land would get something like 10 years of time to lay fallow and regenerate. The herders wandered all over the countryside, mitigating their impact on the land by never overgrazing. These two groups coexisted and traded. The farmers needed animal products to eat and make tools, as well as their dung to fertilize the soil. The herders needed the grains the farmers grew to consume while they herded their animals.
Cue European involvement: After colonization, Europeans implemented techniques that had worked in Europe to maximize production of the land. This included: less crop rotation/higher percentage of land in use for farming, much larger herds of animals, and less migration. In Europe, crop rotation exists but generally under a 2 or 3 field system. In africa they had used a 10+ field system. This means instead of 2-3 years of laying fallow to regenerate nutrients, they let the soil regenerate for 10+ years. The change to the European system temporarily increased output but quickly degraded the soil. Simultaneously, the herders were forced to increase their herd sizes as well. Borders and properties also forced them to restrict their migration patterns, putting more stress on the land and leading to overgrazing and trampling of the topsoil.
The population exploded as well. There were three main components to this. Firstly, food supply had skyrocketed. Secondly, sanitation techinques were introduced. Thirdly, standard number of children in the culture had been very high to both help on the farm/with the herd and to make up for the high infant mortality rate. With a lower infant mortality rate, increased food, and same cultural tendency to have many children, the population increased dramatically.
The stress on the land damaged the topsoil, decreasing plant life. Less plant life led to more erosion. More erosion led to worse topsoil and less plants. This all led to less local water as there was less topsoil and plants to hold the water in place. With less water and more people to take care of, the Europeans tried to help by creating wells. This temporarily worked, but it focused animal and human activity around these wells, completely destroying any remaining topsoil near these sites. The water table quickly dropped since there was high demand and little water to replenish it. The Sahel quickly became more and more inhospitable.
So yes, you could say that the sanitation techniques, pesticides, technologies, and everything else we introduced them to has increased their standard of living. However, their way of life had not only worked for countless generations but had been a part of their culture. We forced them to trade that for our system, with the added bonus of more frequent and more intense droughts, borders and property lines that restrict their movement, and a population too large for the ecosystem it occupies.
I think the issue is the perspective we unknowingly take when we look at the situation. We see their pre-involvement style of life as less civilized or even barbaric, but they had been a self sufficient complex culture and we took that away from them. It's hard to say the standard of living is higher in Africa because when you assess it by looking at infant mortality rate, technology use, or other western metrics, it has changed for the better from our perspective. However, droughts are more frequent and intense, the ecosystem struggles to support the population without outside help/involvement, and their way of life has made impossible. Increased wealth does not lead increased happiness, but drought, overpopulation, and political instability do lead to unhappiness.