Well yeah. I wonder sometimes why microorganisms/pathogens don't evolve in a more devious way than they actually do. Would there not be an evolutionary pressure for all of them to have as long an asymptomatic-but-infectious period as possible?
In fact, why haven't they all evolved to become symbiotic, and actually help the host survive longer? Any microorganism that did so would surely spread further and survive longer than one that killed the host.
Toxoplasmosis seems to behave the way I'd expect such things to - actively changing the host's behaviour to make it spread the pathogen more rapidly. I don't know why they don't all end up like that. Why doesn't COVID turn people Republican? That would be a successful strategy for it.
I think one way you should think of infectious pathogens is that some are hidden ninjas dodging the immune system, while others follow the "slash and burn" philosophy. Flu, SARS, Ebola are great examples of the slash and burn approach. These viruses don't care what happens to the host, just as long as they make as many copies of themselves as soon as possible and spread to others. And it works. With many of these viruses, you're highly infectious for only a short time, but that's sufficient to cause massive outbreaks/epidemics/pandemics.
But there are many examples of pathogens taking the hidden ninja approach. Most humans are infected with viruses like CMV, EBV, HHV-6, HPV, and other weird ones like anelloviruses. Many of these viruses can integrate themselves into your DNA, making it even harder for you to clear these viruses. But these viruses have the ability to evade your immune system and can reactivate long-after your initial infection. Other examples are like Herpes Simplex or Varicella. These viruses can hide in your neurons, only to reactive years/decades later, and suddenly you're stuck with a nasty case of the Shingles.
Then there are the viruses that nobody knows what they do, if anything to us, like anelloviruses. The past decade has shown the microbiome is really important to human health, but the focus has been mainly on bacteria. Our skin, intestines, lungs are teeming with bacteria, yet we don't react to them in a classical "I get sick and have a fever" type of response. They've even given bacteria from the intestines of fat mice and transferred it to normal, skinny mice. Guess what happened? The skinny mice became fat. These are the subtle effects that are important, and in some ways, our immune system is trained by the microbiome. It is known that there are many more viruses in humans compared to bacteria, so they could also be playing similar roles in human health.
Then there's parasites. Millions of human are walking around this planet with several inches/feet of worms in their intestines, and never know it. Yuck. Good thing we use ivermectin for legitimate reasons and not to feed the egos of antiscientific people who want to use it for unproven purposes.