Not necessarily, and vendors don’t only do it to reduce competition, and not all vendors do it either.

As a consumer, having 50 nearly-similar options to choose from is arguably worse than having only a few. With 50 choices you’ll get an entire sub industry devoted to “helping” you make a choice, and you’ll likely miss out on certain economies of scale.

As a vendor, it’s a lot easier to understand, support, and build products for your customers if they are only using your products.

There are obviously negatives to vendor lock-in, but framing it as entirely negative is misleading.

If I were to pick one option out of 50 competitive products completely at random, I'd generally expect that to be better than the counterfactual monopolist alternative.

You should read what I wrote more carefully, nowhere did I claim that monopolies make better products.

You said that it would be easier for a vendor if it could expect to monopolise its customers.

Whilst that is doubtless true, that does not make anything better for customers.

I said nothing about monopolization, I would appreciate if you would not mischaracterize what I said.

If a company’s customers solely use their product, and not a mix of products, it’s much easier for the company to support and build new features for their customers. This is just a fact of reality, and one benefit of customers limiting the number of products they use.

Pointing out beneficial properties of consolidation and specialization doesn’t mean I support monopolies—I absolutely don’t.

Indeed:

Ideally, there would be one car. Ford. Ford would be the only vendor for cars, and Ford would be the only car vendor. We'd have the technology approved by Ford and all of the technology approved by Ford, including black paint, carburetors, tetraethyl lead, and, through a special deal with Radio (formerly RCA), AM radios tuned to Radio, the only Radio company and station in the world.

These vehicles would be simple to maintain, in that the only maintenance option is to ship them to Ford, and simple to customize, in that you cannot.

And anyone who attempts to modify their Ford would be subject to legal penalties, up to and including bomb-making, just as if they'd tried to destroy any other institution.

Wow, that's not at all what I'm saying. Did you notice how I offered no prescriptive nor normative statements? I'm just observing that there are tradeoffs involved--there are some beneficial properties that emerge as the number of choices decrease (along with a bunch of detrimental ones). Pretending like those don't exist does nobody any favors.

Since you asked, my opinion is that there's a healthy tension between too many choices and not enough choices, and we should strive to maintain that tension. Which requires an objective understanding of the tradeoffs, instead of knee-jerk reactions to the phrase "vendor lock-in".

What counts is not the quantity of choices its the complexity and cost of failure especially if the choices are interrelated with other choices and the cost of failure increase with successive badly chosen choices.

Standardization drastically reduces the cost of choices by letting you make them independently, a healthy market increases the chances that there will be many good choices, transparency increases the chance that you will pick one that is good for you.

A small number of complicated interrelated choices would be manifestly worse than a large number of independent mostly good enough choices. This is why its mostly ok that there are a billion different cars. Most of your choices are good enough for most purposes and you don't have to pick your phone, your route home, your brand of gas station based on your car or options.

Having few choices is virtually always bad. The converse is a difficult position to defend when instead of fewer choices one nearly ought to always wish for easier ones.