G: TL;DR (categories only):
Lobbying changed from small-scale, relationship-driven, and episodic (1950s–70s) to industrial-scale, permanent, data-driven, and narrative-engineered (2025). The shift is both quantitative (orders of magnitude more money, actors, and touchpoints) and qualitative (what lobbying is and how power is exercised).

Quantity: how much, how often, how many

1. Scale of money

50s–70s: Millions (in today’s dollars), concentrated in a few industries (defense, oil, unions).
2025: Billions annually, spread across nearly every sector (tech, finance, healthcare, crypto, energy, defense, agriculture, etc.).

2. Number of actors

50s–70s: A limited set of firms, trade associations, and unions.
2025: Corporations, trade groups, think tanks, NGOs, shell orgs, donor networks, influencers, law firms, and PR shops—often layered to obscure origin.

3. Permanence

50s–70s: Lobbying surged around specific bills or crises.
2025: Lobbying is always on—standing teams embedded year-round.

Quality: how lobbying actually works

4. Personal persuasion → systems management

Then: Handshakes, relationships, favors, and direct access to lawmakers.
Now: Regulatory capture, revolving doors, staffer pipelines, pre-written legislation, and policy frameworks delivered turnkey.

5. Policy influence → agenda control

Then: Lobbyists tried to change votes.
Now: Lobbyists shape what is even discussable—what gets studied, framed, delayed, or quietly excluded.

6. Transactional → narrative

Then: “This bill helps my industry.”
Now: Full narrative ecosystems—white papers, expert panels, media talking points, astroturf movements, and algorithm-optimized outrage or reassurance.

7. Human judgment → data optimization

Then: Intuition and experience.
Now: Polling, micro-targeting, A/B-tested messaging, donor analytics, and real-time feedback loops.

Structural shifts that didn’t exist before

8. Regulatory density

50s–70s: Fewer, simpler regulations—less surface area to capture.
2025: Vast regulatory codes mean influence happens in agencies and rulemaking, not just Congress.

9. Revolving door normalization

Then: Present, but socially constrained and limited.
Now: Expected career path—staffer → lobbyist → regulator → consultant.

10. Legal hardening

Then: Fewer campaign finance loopholes; corruption looked like corruption.
Now: Influence is often legal by design—laundered through PACs, nonprofits, and procedural compliance.

Third category (often omitted): Visibility vs legibility

11. More visible, less understandable

Paradox:
- We track spending better than ever.
- We understand causal influence worse than ever.
Influence is fragmented, indirect, and plausibly deniable—hard to point to, easy to feel.

Bottom line

1950s–70s: Lobbying was a pressure.
2025: Lobbying is an environment.

日本語（にほんご）補助（ほじょ）文：
昔（むかし）は圧力（あつりょく）、今（いま）は環境（かんきょう）。 — In the past it was pressure; now it is the environment.