It's more the case drones have not meet their counter yet. It's kind of logical to see expensive AA systems designed to shoot down expensive planes struggling

It's more the case drones have not meet their counter yet. It's kind of logical to see expensive AA systems designed to shoot down expensive planes struggling to answer swarm of cheap drones cost effectively. But the good performance of very old systems like Gepard indicates solutions exist. For example, systems with a decent and modern radar plus a few short range low caliber and cheap AA guns will probably get designed and fielded in the near future. And new weapon systems is not the only answer. Jamming also has proven to be effective. And even simple doctrine changes can be effective. Drones are enjoying an happy time, but it will end and to a degree already has (tb2 is far less prevalent for example).