I remember those colorfoul desktop Macs with the transparent backs, my school bought a few. I remember thinking how excitable they were, and tht the world would never shift on the premise of shiny colours (lol boy did I get that one wrong). But I have always also had the feeling that, in order to be positioned to make that push, Mac must have achieved some deep market penetration in some way that I was not aware of, some story I never heard. You don't deploy a strategy like that without long arms and deep knowledge. And deep pockets. It's not a starting point, it's a pivot.
Yes, but that push happened long before and after the iMacs were invented.
The big selling point for the original Macs in the 80s was the invention of DTP or desktop publishing. It was the first computer system with good enough GUI to be able to manage to do that. It took Windows long enough to catch on here. Apple was so invested into DTP, that they even produced their own series of laser printers back then, which were bulky and slow things by modern standards. Stuff like the Laserwriter IINT. Inkjet printers became popular much later. For a long time the program to go for DTP was Quark XPress. For other documents Aldus Pagemaker.
The other point was image editing, namely Adobe Photoshop, which for a long time only worked on Mac.
It's not like other computers like Atari didn't try to carve their niche here as well, but they all failed.
This is why Apple still has such a big user base in the creative and graphical industry. Also when Quark and Photoshop later was ported to Windows many people in the print and design industry still preferred Mac, due to it giving more precise and better output for the printing press. Also it was easier to use.
The iMac was not supposed to be a computer for professional work. Of course you could still do it. But instead it was supposed to be a great looking and easy to use computer to hook you up onto the internet.
Compared to what you had to do connect a Windows PC to the internet the iMac was dead simple, way better looking and way less cluttered. It also had a very competetive price point. It was also one of the first computers to only come equipped with USB ports, which was a radical decision back then.
What to say - it worked. The iMac was a great success and sold like hot cakes, bringing in much needed revenue to the decaying company. What really changed Apple then though was the launch of the iPod.
At the time when Jobs joined Apple again Apple had no deep pockets any longer. It had about almost a decade of decline behind it. And it was rumored to be a candidate to get bought by a competitor, namely Sony. It was Jobs who gave Apple deep pockets again.
Jobs also then made some bold decisions later in his career.
After iMac came out the biggest improvement on Mac side was the introduction of MacOS. Apple's own OS for Mac at the time back then was outdated and lacked features the competition had, like memory protection or real multitasking. Apple tried to develop a successor for the old system in the 90s and had an internal project named Copland, but it failed to deliver. Apple then was in negotiations with Be to buy BeOS, but they demanded probably too much. Instead the board went with NeXT and the rest is history.
MacOS under the hood is a continuation of NeXTStep, sharing lots of APIs and concepts, like the dock.
Another of the problems Mac had when he came back was the Power CPU architecture. Intel was taking off over time, and Power CPU failed to be on par in terms of power consumption for laptops and computing power.
In the past Apple ridiculed Intel for being too slow. In 2005 Apple switched then the whole Mac lineup to Intel CPUs, which was the second time Apple switched the CPU architecture. First one was from Motorola 68000 to PowerCPU, so the PowerMacs. Which is what made Apple computers good again for many most people performance wise. Intel then again was ditched in 2020 due to too many hardware errors, unkept promised and bad QA for the ARM based Apple Silicone architecture.