You're not alone.  I have observed casually that there don't seem to be as many bees and butterflies in the past few years.  Pollinators need nesting habitat, nectar and pollen to be successful.  When we eliminate one of these needs they move on or decline.  Books to read on the subject include the following books by Doulas W. Tallamy: "Bringing Nature Home" & "Nature's Best Hope".  More info on pollinators in the attached links:
https://www.canr.msu.edu/resources/smart-gardening-what-makes-a-pollinator-rare-or-endangered
Michigan Pollinator Initiative-MSU - lots of info here, check out the 'pollinator champion' course subjects
https://www.canr.msu.edu/news/msu-survey-to-understand-knowledge-attitudes-toward-pollinators - a survey you might participate in....
https://news.umich.edu/michigan-bee-study-both-habitat-quality-and-biodiversity-can-impact-bee-health/
https://www.healthylakes.org/latest-updates/protecting-pollinators-native-plant-prairies-preserve-vital-indiana-ecosystems
Causes of pollinator decline include habitat reduction from human development and agriculture and use of pesticides.  You are helping by planting native flowers and grasses.  Consider planting a native pollinator mix (flowers & grasses) in part of your yard as I did in part of my backyard.  More info here:
Establishing Pollinator Habitat-MSU
Invite Pollinators By Creating a Habitat-SG-MSU
Native Prairie planting example-MSU
Neighborly Natural Landscaping Info-PSU
You can also contact Prairie Moon Nursery (prairiemoon.com) and Prairie Nursery (prairienursery.com) to get their catalogs as both sell a variety of native plants & seed mixes. They also have good instructions on proper site preparation and seeding steps. Other more local seed/plant sources include Michigan Wildflower Farm (michiganwildflowerfarm.com), Wildtypes (wildtypeplants.com) and East Michigan Native Plants (eastmichnatives.com). MSU Extension does not endorse any retailers or brands. I wish you good fortune in increasing pollinators in your neighborhood!