You'll have plenty of time to save your pennies for that bottle, I think. It's true that some of the entry-level market is being threatened by small competitors – Pixelmator, acquired by Apple a while ago, was really starting to look like a credible threat to Photoshop. And the various Affinity apps are certainly competent at what they do in the various graphics arts niches they serve.
However, the reason I'm skeptical is that these alternatives have a long way to go in terms of the proven track record that the Adobe ecosystem has in the prepress field. The Adobe apps work together really well: files from one app seamlessly integrate into documents of another app; color settings sync across the entire platform; there's a uniform predictability to it all, which is exactly what you want in prepress; fewer surprises. And the preference for Adobe in the prepress field feeds back into the layout artists, production artists, designers, photographers, etc. who eventually send their files for output. When your client's output house says they want InDesign files, you provide them InDesign files.
Now, there's a gaping hole in this theory: online content, where prepress isn't a thing and open, flexible display frameworks accept a wide variety of standard files (JPG, SVG, that sort of thing). Any app that can blurt out a JPG can integrate into a system like this, and the stakes are a lot lower; ain't no embedded fonts in a JPG, and nobody cares as much about color accuracy online because it's fundamentally a lot less achievable than it is in print. So now you've knocked down several of Adobe's key advantages and these alternative tools are suddenly looking more viable.
And then you start to get customers who are new to the branding game, working on a shorter timescale with a less developed strategy, who just need their thing printed – and you can get away with certain compromises in terms of quality and accuracy – and now you're just sending a rando PDF to a web form to get it printed on some poorly maintained digital duplicator and it's Good Enough®, and who cares where the PDF came from because it will never get used again. Maybe the customer eventually changes course and seeks out better quality output and ends up back in the Adobe sphere, and maybe they don't.
In the end, the real danger to Adobe's dominance really is Good Enough®: when accuracy, quality, and wider compatibility aren't important factors, an adequate tool will be a better value proposition than the comprehensive battle-tested tool, and the adequate tool has nowhere to go but get better over time. However, Adobe has at least a decade's lead on these tools and untold amounts of buy-in from their userbase, and despite evidence to the contrary, Adobe is not a stupid company. There's good odds they will maintain their market position for the foreseeable future.