I wonder who is better in terms of whole if considered. Speed, latency, reach, accessibility and affordability.
Starlink and 5G don't have that much to do with each other--they compete for different customers.
Starlink systems currently require a large receiver the size of a pizza box to uplink to satellites. It is unlikely that this will be miniaturized to fit into mobile devices within the next decade or so.
5G is a short-range, high-bandwidth technology designed to allow high speed data in urban environments. Starlink is a long range service designed to give Internet to people away from urban centers. They are not in competition
While you could use Starlink to provide network access to a 5G tower, it wouldn't make much sense as Starlink doesn't provide that much bandwidth. According to the FCC filing, Starlink satellites have a max individual throughout of 20gbps and a single 5G client can expect speeds north of 500mbps. That means a single 5G tower which is connected via Starlink could only support 40 people (at max utilization) even with a dedicated satellite.
Starlink is not a member of the DSN and won't be anytime soon. The satellites are all facing inwards and in rather low orbits. Maybe, low-orbit stations or spacecraft will be able to hook into the network for internet though.
If you want to read more about this, check out this article.
I don't think so. Delivering end user service is far more profitable than wholesale. And the full Starlink plan is having the satellites work as a global internet backbone, with the end users directly connected to the network.
Think about it this way 10 million users @ US\$ 100/user = US$ 1 billion/month in gross revenue. The largest cost of a global ISP is precisely its network and the full starlink will allow for them to directly access all worldwide major IXP (internet exchange points), perhaps never having to pay a dime to purchase global internet transit that even huge ISPs like Time Warner and Comcast have to pay (because they don't have a global network hence they don't qualify to peer with the big global players like L3, NTT, Tata, AT&T, HE, Cogent, ...).
In the end rolling out fiber isn't cheap but its an investment that can last for many decades.
Bandwidth requirements for a 5G cell is very large. Starlink simply won't have the spare bandwidth to do "whole selling".
This will almost certainly be the case for some 5G (and even 4G) cells.
Starlink provides, at best, 20Gbps per satellite with the current fleet with real bandwidth likely to be 1/3 to 1/2 of this. This is nowhere near enough for a 4/5G cell with significant subscription, but in the cases where a carrier wants to extend coverage down an interstate or through a rural area then it will be significantly cheaper for them to use Starlink as a backhaul than to run fiber. Starlink may or may not be more attractive than other constellations, depending on the carrier's tolerance for latency and the pricing structure for wholesale.
Starlink is a very interesting case - it has a constant network speed availability for a given area (within its coverage latitudes) over a very, very non-constant population density.