This is a legitimate topic of discussion, and is interesting in different ways to different people, distracting to some, even irritating to others. This is the nature of debate and disagreement and is not a bad thing.
M is a not a point product, it is a system, an entire product line. Product lines have many organizations behind them - design and development, supply chain , manufacturing and test, marketing, sales, and distribution. These functional organizations are probably comprised of people within their repsecitive departments in the imaging division that is responsible for many other product lines (DSLR, Mirrorless, compact). Currently the M people within the mirrorless division have to run the customer support for previous models, production of current models, and development of future models). Makes sense doesn’t it - past present future.
Past products are an easy discussion. They are discontinued because marketing and sales determine that the current product that replaced them obsoleted the discontinued models (keeping the older models sometimes makes sense if the pricing tiers can have enough separation to minimize confusion and overlap while maintaining profitability- no one wants to lose money keeping older models around). Look at Panasonic G80 vs G90 (they decided to keep G80 around)
Current products (M5, M50, M6...) that is more complicated because not only does the manufacturing cost, sales price and competition from other brands, and sales trends have to be considered, but also what future products are in the pipeline (Canon as well as other competitors) that the current products have to compete with for customers and profits. They have to stay competitive and compelling to stay in business.
In product development, time is always a resource you can’t afford to lose. So of course there is a future product lineup in development. Whether these will be brought to market is a sales and marketing decision that requires a crystal ball ( which none of us have, not even Canon or other manufacturers).
Keep in mind that product line decisions (past, present, future) are made at the board of directors level, and the CEO has to make his best plans and proposals and seek board approval. These decisions don’t happen quickly, large corporations don’t turn on a dime. That is usually a good thing.
But to answer the original question: Will EF-M survive? Yes because it is a currently successful product line and will continue on until conditions change to the point where it needs to be discontinued (for the above reasons). One can hope it is because a newer model has made it to market - in what form and features that would be is anyone’s guess. Even Canon who test different variations of a new model in development don’t know until they roll up all the feedback from field testers and they have to commit to the configuration for manufacturing and marketing ramp.
One thing to note: Canon probably doesnt have any particular aversity to supporting 4 lens mounts (EF, EF-S, EF-M and EF-R), logistically it is not difficult since manufacturing systems are so automated by computers, as long as it doesn’t cause customer angst from confusing product lines.
One other thing: the large sales volume of M is both tactical and strategic. It is tactical because it contributes a big part of revenue and profits which is a necessary thing when you are a publicly traded company. It is strategic because it gives them the advantage of scale; this translates into an operational and manufacturing cost advantage that affects their high other end higher profit margin products. So M contributes to the bottom line in a direct and indirect way. Whether it gets credit for the indirect impact to Canon’s bottom line is not known - that is an internal Canon business policy decision.