I first learned Eagle 2.6 (yes, under MS DOS) in my vocational school in 1996 and I'd been using it continuously since then. After 30 years, it was particularly painful to see it go. But unlike other popular historical PCB EDAs (
see P-CAD), it's not completely dead. Sure, the official successor Autodesk Fusion Electronics is a cloud-based garbage, but it's something. And Altium and KiCad have almost perfect Eagle importers now. And if all else fails, there are cracked versions of Eagle floating around, even though their quality varies.
Personally, I decided to switch to KiCad. As mentioned by
@alex_, it's much less user-friendly SW, but current development team has improved its usability tremendously over the last few years. Sure, its Orcad-like schematic editor is still quite hostile, since a bad mouse move can create unwanted shorts with zero warning (Altium 15 was even worse). That really pissed me off, so I paid KiCad developers to at least add
visual indication it's about to happen.
KiCad's SCH-PCB sync is a real pain, in fact, it's the worst and most complicated implementation I've seen in any PCB EDA. And unfortunately the sync menu (F8) has been getting yet more and more complicated with every major version. I paid them to fix
the most egregious problem with it, but it will work only if the user enables in settings. I actually asked them about Eagle-like realtime PCB sync -- it's not anywhere on their future development roadmap, but it would be doable. It would require a lot of work though, so they gave a price quote for which you could buy a used car...
I'm also currently negotiating to sponsor development of Block Drag function in PCB editor which will work almost like Move in Eagle. Frankly I find it incomprehensible that something so basic could have been missing in KiCad for so long. It will be the most expensive feature I'd sponsored yet, but on the other hand, it's a few years of Autodesk Fusion subscription price. Except all KiCad users will get it and can use it in perpetuity. Still, if you wanted to pitch in some money for these features, let me know!