While it's hard to come by numbers, there are several non clone candidates that sold quite well:
- Sirius 1/Victor 9000 1981-1984- Outsold the IBM-PC in Europe by far not at least due better hardware and a headstart of almost a year. It got screwed by company politics in the US ignoring the European success.
- Sanyo MBC-550 1982-1986
- Siemens PC-D 1982-1986
- NEC PC98 family 1982-2004 - Last complete new model in 1992, more than 18 millions sold, the essential Japanese PC. It had it's own fellowship of compatible machines effectively making it the PC standard in far east. (*1)
- TI Professional Computer and Portable PPC 1983-?
- Tandy 2000 1983-1988 - Successful in the US, not much outside.
- Olivetti M24 1983-1989 (also repackaged as AT&T 6300 and Xerox 6060) - Quite considerable sales in Europe. For example the defacto standard for everyone working in accounting and taxes in Germany during most of the 80s way into the 1990s.
- TA Alphatronic P50/P60 1985-1990 - 80186 based office system.
- Amstrad/Schneider PC1512 1986-1990 - Quite successful in the UK and Germany.
- Fujitsu FM-Towns 1989-1997 - A Japanese household name.
and not at least
Some machines with lesser, but still noteworthy sales:
There are many more that had some impact, but hard to judge - also while being somewhat Euro/US-centric, it leaves out many developments outside the UK and Germany.
If one really wants to go ahead and make up something like 'waves', this this would support three rough categories:
- Early systems predating or parallel to the introduction of the PC. If not cut due internal issues, most vanished in the mid 1980s
- x86/MS-DOS machines introduced after the IBM-PC offering considerable enhancements, if at all only in part compatible, most of them rather short lived.
- Business and home machines developed after the IBM-AT, often in some way compatible, but still different enough to need custom versions of most games/applications.
Bottom line: Several less than fully compatible machines/families enjoyed huge success, past the claimed 'early ones', some designed way after the PC-AT, which essentially defined the standard.
The holy grail of 100% compatibility was for most parts only present in the US. And even there some, like the Tandy 2000 could hold up. I'd still say it was mostly a sales argument for a few companies, carried by willing journalists.
*1 - Here a little indicatorhow popular the PC98 is/was in Japan: A new mini-PCI-E card, for Laptops, that plays the PC98 startup sound when booting.