Note that collecting consent still doesn't give you carte blanche to collect all the datas. The principle of data minimization still restricts you to only the data you need for the purpose you state when gathering consent.
Consent, as you point out, is only one aspect of this.
Facebook and Google are still around. There is absolutely zero risk of any significant GDPR fine as long as the biggest offenders are allowed to run freely.
I think it would be unsafe to assume that there is zero risk of significant GDPR fines on the basis that the regulatory bodies have not picked a battle with google and Facebook.
Smaller organisations that seem to be doing less to respect GDPR are probably an easier starting point for regulators to begin enforcing the law.
Also: How are Google and Facebook offenders of GDPR?