All of the above plus a lack of respect from the business for the value a competent ESO/ERT can actually deliver.
Add in the Dunning Kruger effect of many ESO/ERT and the compounded debasing that occurs when operational vs conversational competence conflicts. For a truly high performance skillset in a field this diverse it needs routine high fidelity training, high levels of personal accountability and responsibility and a dedicated work ethic, unfortunately these attributes are exceedingly rare individually let alone as a combo.
1 2 and 3: for alot of sites the allocation of refresher training or upskilling can be few and far between, causing ESOs to loose interest or feel less relevant causing poor operational discipline
for some site even with strict shedualed training days ERT with production roles are often not released to attend regular training contributing to skills gaps and skill fade over time....but of course still counted as an operational number which in turn can demish a healthy ES/ER culture
It depends on the context, but if were talking about career growth, Cultural Perceptions would have the most significant long-term impact.
ER roles are often seen as secondary to operational priorities rather than a critical function that ensures business continuity and safety. It's this mindset which tends to limit investment in training, leadership pathways, and long-term career opportunities.
I'd say number 2. I often say the E in ESO stands for Everything Service Officer(drug testing, security, HSE).
If we changed the culture, If on site Emergency Services were treated like professionals and in turn acted like professionals, 1 and 2 will follow.
1 & 3. But for those who are able to use the tools and knowledge and also is exposed to real life events off site will gain more than being put through a simulation that is controlled on site.