Quantifying the long term costs associated with self hosting the Bitcoin node? In this question I discussed the option of self hosting the Bitcoin node vs. using 3rd party services with API access. I quoted a colleague who said that &quot;for every coin we wish to support, we will be required to hire a dedicated expert developer to maintain each node at a cost of $40,000 per year per node&quot;.
Although this was not the main point of my other question, I received a polarizing response to this quote.
For example, the user @Anonymous commented:

Where could they have possibly got the idea that maintaining a bitcoin
node costs $40,000 a year?

In response, the user @chytrik wrote:

Perhaps not for bitcoin, but for some poorly developed altcoins that
number is maybe too low – chytrik

A similar sentiment to @chytrik has been echoed by @Murch♦:

I agree, developers with a cryptocurrency background is not neither
cheap nor abundant. Obviously, it depends on your location, but I
suspect that you may find that $40,000 p.a. to be actually highly
optimistic. In the US, you'd probably be looking at $150k+ per
position (salary+rest).

Since this site is for Bitcoin, the focus of my question will be exclusively on Bitcoin.
Is there a practical way of quantifying the cost associated with self hosting the Bitcoin node? This includes the cost of hosting, scaling and hiring a competent developer to setup and debug the node. Obviously, a big part of the evaluation is likely to depend on the number of expected transaction so let's assume for this example we are dealing with an app that will scale from 5,000 to 500,000 customers at some point or from 500 to 50,000 requests per day.
What is a practical way of quantifying the long term costs involved and what type of maintenance/upgrades would a developer be required to do in the long term?
Is there a practical way of quantifying the cost associated with self hosting the Bitcoin node? This includes the cost of hosting, scaling and hiring a competent developer to setup and debug the node.

Depends on the business. If it's a startup you can always hire a developer for initial setup. If you experience any issues in future, pay another developer per hour for a specific work.

What is a practical way of quantifying the long term costs involved and what type of maintenance/upgrades would a developer be required to do in the long term?

Type of upgrades/maintenance can involve anything mentioned on https://bitcoin.stackexchange.com or https://github.com/bitcoin/bitcoin/issues