It isn't. The majority of tech companies are speculative and funded by venture capital, and what's worse, many of the largest companies, which actually do generate revenue, are monopolies
What this means is that efficiently competing is only a viable strategy if you can convince a small pool of potential investors - many of whom think "competition is for losers" - that it's a good play, while also avoiding being bought out and crushed by one of a few trillion-dollar companies
The dynamics you're describing are those of an open market, and with wealth disparity at an all-time high (so your customers have less influence on average) and financial scams fairly rampant due to decades of lax enforcement, most companies right now are not effectively operating in an open market
Buying SaaS is trendy conventional wisdom. It has benefits and downsides, but in my experience the biggest benefit is that VCs think it's smart to do and also often benefit from a company buying the products of other companies. Whether it helps with things like making products faster or better overall is close to immaterial in this environment