His last season there before he quit they got 91 points. Real were with 100.
Barca's low point in last 10 years or so was on 56 points and 6th place before Rijkaard took over who himself did a remarkable turnaround there as they had a bad few years before that. Financial dynamic in La Liga have changed a lot since then also with the top 2 going further apart from the rest every year.
Guardiola did very well given the favorable circumstances at Barca (not much more you can expect except maybe not leaving the way he did and his transfer record outside of Ex Barca products), but won't put him in the highest league yet vs manager's who have proven themselves working from the bottom upwards and across different scenarios and clubs that were outside their comfort zone many a time.