As petty as it might be with such a positive piece, I'd limit this to the
human world and qualify the statement with the point that quite a lot of the things that we see as definitive improvements are limited in scope and have long-term potential for devastating effects for future generations. I say this as I think the
natural world has had better diversity and sustainability. Human actions in terms of resource acquisition, use, and conservation over the last few centuries have risked incredible harm to the long-term quality of life for our species and the very existence of countless others that ensure the durability of ecosystems. It's only really better if you look at a narrow window of time.
Equally, I'd agree that things are shifting to greater overall happiness and less pain in parts of the world but I don't think we should let that make us complacent, render us oblivious to the countless pains in the world that fuel that ability to be 'better,' or cause us to forget the capacity for the tide of progress to go back out. I don't think it's negative to keep that in mind while treasuring changes.
For instance, it's increasingly great to belong to some demographics in many areas of the West, and the world, right now but the majority of the world continues to pay inexcusable prices for that, whether that's with us outsourcing worker suffering to places with no labour rights or the way our massive on-going history of colonialism introduces astounding pain in other cultures. The writer refers to transgender tolerance but how many places had, or have, diverse genders that we tried, and try, to wipe out via using various forms of power to impose our binary system?
Similarly, it depends on how you define 'better'. The way neo-liberalism continues to drag politics rightward in countless places, including Western countries, definitively introduces greater inequality and harm while the illusory idea of meritocracy makes people think those changes are an improvement or actually yield greater practical freedoms. It's often seen as better by the population but I'd argue it's not in many contexts.
However, I'm sure this is just me being cynical and makes it sound like I'm not appreciative of changes for the better!

I'm overjoyed by many of them, fascinated by them, and astounded by them. I value the astonishing progress that science coupled with ethics has brought us and will continue to bring us, particularly sciences related to biology. I cherish the way technology allows the people of the world to become more interconnected and appreciative of each other, as mentioned by the wrtier. I'm grateful that I had, and have, access to education or a fundamental income that ensures I'd still survive even in hardest times. I'm amazed by books that I get to read about fantastical worlds created by authors or elaborate arguments for how the world should be. There so many things that make me happy.