Opening really old files and getting unexpected results is definitely a legit complaint with CorelDRAW. This is one reason why I tend to convert all fonts to outlines and release/finalize any live text on path effects once I am finished with a
sign design. The type handling in CorelDRAW has changed over the years. Even if you have the exact same font files installed that were used to create an archived design back in the mid 1990's the type may go all wonky when that old file is opened in a much newer version of CorelDRAW.
Still, I see no legit reason for them to just arbitrarily decide to completely disable file open/import functions for any CDR file saved in a version earlier than version 5. It forces a company to keep an old
computer alive running an older version of CorelDRAW that can open those files and save them to a later, more compatible file version. This is a serious knock against them regarding comparisons to Adobe Illustrator. You can still open a 30 year old Illustrator 88 file in Illustrator CC 2018.
I've been at my current job for almost 25 years and have been doing
sign designs and other
computer graphics work for almost 30 years. I know the history very well. When vinyl cutters and routing tables started revolutionizing the
sign industry the activity was all very much PC-dominated (MS-DOS then
Windows). Companies developing graphics software for the Mac platform didn't seem to be interested in the
sign industry niche at all. Not nearly as much
sign making software was available on the Mac side. That confined most
sign shops to using DOS/
Windows-based PCs. And on that platform back then CorelDRAW was the only credible choice for mainstream vector graphics software. The alternatives to CorelDRAW were either garbage or non-existent until the mid-to-late 1990's.
CorelDRAW also sold itself pretty well by including a lot of bonus goodies, like fonts and clip art. Adobe Illustrator hardly included squat in the standalone box. Freehand was a little better in terms of bonus fonts and clip art, but it paled in comparison to what CorelDRAW included. Deneba was the only one that really tried to match Corel on the fonts and clip art front with what they bundled in Canvas (over 2000 URW fonts for instance). I remember picking up a competitive upgrade of Canvas 7 for $99. I didn't use the application very much, but the fonts and clip art were worth it.
By the way, the Mac platform still isn't well supported in the
sign manufacturing industry. Gerber Omega is
Windows-only. Flexi and the other SAi applications like EnRoute are
Windows-only (Flexi used to have a Mac version, but not anymore). SignLab is
Windows-only. Our RIP software, Onyx Thrive and Roland VersaWorks are
Windows-only. The LED message center software we use from Daktronics and other vendors is
Windows-only.
This gets into why I use CorelDRAW rather than Illustrator for building up objects in
sign designs. OTOH, there are plug-ins from Astute Graphics (VectorScribe, PathScribe, etc) that add a great deal of technical drawing capability among other things. Too often I wind up back in CorelDRAW anyway when I need larger art board real estate -which gets back to the original topic: Illustrator's 227" X 227" art board limit.
I'm not the one creating these CAD files; they're supplied by customers. They don't care about creating objects with closed paths because they're not applying fills to those objects, much less sending them to vinyl cutters, routing tables, etc. It's just like customers home-brewing their logos or some other artwork, dropping off a JPEG of it and expecting that to work. To these people a digital file is a digital file and because it's digital it should automatically work,
"it's in the computer already!"