The hard part is precisely that they want to reuse that platform, and just replace the engine with a battery and motors. Designing an electric vehicle from scratch today is infinitely easier than an ICE, both in complexity, skills required, number of parts and manufacturing.
I would interpret that data precisely the opposite: designing and manufacturing a new car is hard, swapping out the power plant is much easier. Thousands of Ford and Toyota engineers are doing something and it isn't redesigning an ICE engine every year.
The comment was about the ease of making electric cars, which is only happening on the last decade and plenty of companies are popping up.
Yes, those engineers are busy dealing with the complexity I just mentioned.
ICE manufacturers make a platform and use it for years, sometimes decades, with only relatively minor tweaks. The hard part as I understand it is literally everything else about manufacture, something which will be broadly shared with EVs.