I think the bee thing is a good point, but quite a difficult one to pin down. We have kept bees for several years and certainly in the UK I don't think pesticides is a significant factor any more. Monoculture can be a problem, but we do have vast crops of oil producing plants and they by and large encourage bees. Climate change is a large factor I think. When we have very wet springs, the pollinators struggle to get going and tend to stay clustered, not leaving the hive. Constant cold and rain is unhelpful to flying insects. When we do get a hot summer, this tends to create a dearth of pollen (ie "no flow" which only picks up again as autumn approaches - and once again we get cold and wet.
We also have a growing problem with pests and diseases which kill whole hives. Foul brood seems to be becoming an issue and we have not got a grip of the Asian hornet problem. However, it is undeniable that windscreens these days are clean, so insect populations must be diminishing. Mankind is likely to respond as we usually do by trying to apply technology such as genetically engineering for self pollination or even continuing the development of micre pollinator drones. It's the destroy and change method.