Domestic wickets & Captaincy.
Domestic wicket part is easy to explain - damp, under-prepared, soft & green wickets; FC matches played in OCT-DEC period for 65-70 overs per day with substandard balls - one can get bucket loads of wicket bowling line length at 130km on a particular spot. Besides, 70 overs/day of FC match means 13-14 overs of work load - every spell is like 1st spell when it comes to endurance. Add to that is 600+ players FC system, where half of the players don't have fundamental batting skills, when it comes to play moving balls or judging off stick line. And, end it with batting strategy - a team total of 170 can be match winner on such wickets, therefore only a fool will try to stay in wicket for 3 sessions - better is to slog for a couple of hours & try to get a 48 of 58, which can take that 170 to even 256, a genuine match winning batting effort - hind side is Sadaf Hussian, almost Syd Barnes like stats.
Compared to this joke, even if I consider the worst of the lot, Bangladesh League - 98 overs/day in the hot month of FEB to May, on solid wickets that'll need 5 bowlers toiling for 4 days to get a direct result & bowlers that, if required can bowl for 5 spells of 6 overs each in a day under scorching sun for 35-38C heat & 85% humidity, in matches played among top 100 players of the country. If I go to the highest level - that's Australia, it's several clouds above.
The bottom line is - PAK domestics doesn't stress pacers to run for that extra yard.
The second part is a bit complex. Fast bowlers need the biggest backing from their Captains. It's obvious that someone bowling at 150KM with 3 slips, a gully & couple of short in fields, will go for plenty if it goes wrong. You need big heart to operate with fast bowlers - it's like a trade off - go for the kill, risking a run feast.
Since Wasim, PAK is led by some of the most negative, timid & vision less Captain, whose approach to the game was safety first. They have systematically discouraged bowlers with pace. A classic example can be Md. Sami - at 23 (ok 25), when Inzi took charge, he had every thing to be a tearaway fast bowler - BUT, he was used as a container, which ended his career. Same Sami under Imran or Akram would have been totally different bowler as they would have used him for 4 spells in a full day for 14 to 16 overs max. It's same with Wahab - at mid 30s, he is clocking 150KM+ - this guy debuted in 2010, in his 10th year in FC cricket & 7 years after winning the U19 WC. Had this guy been picked at right age, sometimes in 2004-05, could have been one of the AT fastest bowlers ever. I can name few more as well, but I guess, it's explained enough. Shoaib was a superstar by the time Akram was sacked as Captain, otherwise I can safely say his career would have been half.
These are the 2 prime reasons why IND in it's first 70/80 years hardly had any fast bowler coming or lasting - what little came, perished in couple of years under similar mentality Captains & lifeless wickets where the faster you bowl, the quicker you are hit to the boundary.
Unless PAK's domestic wickets are changed, in few years time PAK will lag Afghans in terms of pace & BD in terms of skills in fast bowling department - already are behind IND.